draft-ietf-dime-nat-control-17.txt   rfc6736.txt 
Internet Engineering Task Force F. Brockners Internet Engineering Task Force (IETF) F. Brockners
Internet-Draft S. Bhandari Request for Comments: 6736 S. Bhandari
Intended status: Standards Track Cisco Category: Standards Track Cisco
Expires: October 22, 2012 V. Singh ISSN: 2070-1721 V. Singh
V. Fajardo V. Fajardo
Telcordia Technologies Telcordia Technologies
April 20, 2012 October 2012
Diameter Network Address and Port Translation Control Application Diameter Network Address and Port Translation Control Application
draft-ietf-dime-nat-control-17
Abstract Abstract
This document describes the framework, messages, and procedures for This document describes the framework, messages, and procedures for
the Diameter Network address and port translation Control the Diameter Network address and port translation Control
Application. This Diameter application allows per endpoint control Application. This Diameter application allows per-endpoint control
of Network Address Translators and Network Address and Port of Network Address Translators and Network Address and Port
Translators, which are added to networks to cope with IPv4-address Translators, which are added to networks to cope with IPv4 address
space depletion. This Diameter application allows external devices space depletion. This Diameter application allows external devices
to configure and manage a Network Address Translator device - to configure and manage a Network Address Translator device --
expanding the existing Diameter-based AAA and policy control expanding the existing Diameter-based Authentication, Authorization,
capabilities with a Network Address Translators and Network Address and Accounting (AAA) and policy control capabilities with a Network
and Port Translators control component. These external devices can Address Translator and Network Address and Port Translator control
be network elements in the data plane such as a Network Access component. These external devices can be network elements in the
Server, or can be more centralized control plane devices such as AAA- data plane such as a Network Access Server, or can be more
servers. This Diameter application establishes a context to commonly centralized control plane devices such as AAA-servers. This Diameter
identify and manage endpoints on a gateway or server, and a Network application establishes a context to commonly identify and manage
Address Translator and Network Address and Port Translator device. endpoints on a gateway or server and a Network Address Translator and
This includes, for example, the control of the total number of Network Address and Port Translator device. This includes, for
Network Address Translator bindings allowed or the allocation of a example, the control of the total number of Network Address
specific Network Address Translator binding for a particular Translator bindings allowed or the allocation of a specific Network
endpoint. In addition, it allows Network Address Translator devices Address Translator binding for a particular endpoint. In addition,
to provide information relevant to accounting purposes. it allows Network Address Translator devices to provide information
relevant to accounting purposes.
Status of this Memo
This Internet-Draft is submitted in full conformance with the Status of This Memo
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This is an Internet Standards Track document.
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on October 22, 2012. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6736.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction ....................................................4
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. Conventions .....................................................6
3. Deployment Framework . . . . . . . . . . . . . . . . . . . . . 8 3. Deployment Framework ............................................7
3.1. Deployment Scenario . . . . . . . . . . . . . . . . . . . 8 3.1. Deployment Scenario ........................................7
3.2. Diameter NAPT Control Application Overview . . . . . . . . 10 3.2. Diameter NAPT Control Application Overview .................9
3.3. Deployment Scenarios For DNCA . . . . . . . . . . . . . . 11 3.3. Deployment Scenarios for DNCA .............................10
4. DNCA Session Establishment and Management . . . . . . . . . . 13 4. DNCA Session Establishment and Management ......................12
4.1. Session Establishment . . . . . . . . . . . . . . . . . . 14 4.1. Session Establishment .....................................13
4.2. Session Update . . . . . . . . . . . . . . . . . . . . . . 17 4.2. Session Update ............................................16
4.3. Session and Binding Query . . . . . . . . . . . . . . . . 19 4.3. Session and Binding Query .................................18
4.4. Session Termination . . . . . . . . . . . . . . . . . . . 21 4.4. Session Termination .......................................20
4.5. Session Abort . . . . . . . . . . . . . . . . . . . . . . 22 4.5. Session Abort .............................................21
4.6. Failure cases of the DNCA Diameter peers . . . . . . . . . 23 4.6. Failure Cases of the DNCA Diameter Peers ..................22
5. Use of the Diameter Base Protocol . . . . . . . . . . . . . . 24 5. Use of the Diameter Base Protocol ..............................23
5.1. Securing Diameter Messages . . . . . . . . . . . . . . . . 24 5.1. Securing Diameter Messages ................................23
5.2. Accounting Functionality . . . . . . . . . . . . . . . . . 25 5.2. Accounting Functionality ..................................24
5.3. Use of Sessions . . . . . . . . . . . . . . . . . . . . . 25 5.3. Use of Sessions ...........................................24
5.4. Routing Considerations . . . . . . . . . . . . . . . . . . 25 5.4. Routing Considerations ....................................24
5.5. Advertising Application Support . . . . . . . . . . . . . 25 5.5. Advertising Application Support ...........................24
6. DNCA Commands . . . . . . . . . . . . . . . . . . . . . . . . 26 6. DNCA Commands ..................................................25
6.1. NAT-Control Request (NCR) Command . . . . . . . . . . . . 26 6.1. NAT-Control-Request (NCR) Command .........................25
6.2. NAT-Control Answer (NCA) Command . . . . . . . . . . . . . 27 6.2. NAT-Control-Answer (NCA) Command ..........................26
7. NAT Control Application Session State Machine . . . . . . . . 27 7. NAT Control Application Session State Machine ..................26
8. DNCA AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . 30 8. DNCA AVPs ......................................................29
8.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 30 8.1. Reused Base Protocol AVPs .................................29
8.2. Additional Result-Code AVP Values . . . . . . . . . . . . 31 8.2. Additional Result-Code AVP Values .........................30
8.2.1. Success . . . . . . . . . . . . . . . . . . . . . . . 31 8.2.1. Success ............................................30
8.2.2. Transient Failures . . . . . . . . . . . . . . . . . . 31 8.2.2. Transient Failures .................................30
8.2.3. Permanent Failures . . . . . . . . . . . . . . . . . . 32 8.2.3. Permanent Failures .................................31
8.3. Reused NASREQ Diameter Application AVPs . . . . . . . . . 33
8.4. Reused AVPs from RFC 4675 . . . . . . . . . . . . . . . . 33 8.3. Reused NASREQ Diameter Application AVPs ...................32
8.5. Reused AVPs from Diameter QoS Application . . . . . . . . 34 8.4. Reused AVPs from RFC 4675 .................................33
8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter 8.5. Reused AVPs from Diameter QoS Application .................33
Application . . . . . . . . . . . . . . . . . . . . . . . 34 8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter
8.7. DNCA Defined AVPs . . . . . . . . . . . . . . . . . . . . 35 Application ...............................................34
8.7.1. NC-Request-Type AVP . . . . . . . . . . . . . . . . . 36 8.7. DNCA-Defined AVPs .........................................35
8.7.2. NAT-Control-Install AVP . . . . . . . . . . . . . . . 37 8.7.1. NC-Request-Type AVP ................................36
8.7.3. NAT-Control-Remove AVP . . . . . . . . . . . . . . . . 37 8.7.2. NAT-Control-Install AVP ............................36
8.7.4. NAT-Control-Definition AVP . . . . . . . . . . . . . . 38 8.7.3. NAT-Control-Remove AVP .............................37
8.7.5. NAT-Internal-Address AVP . . . . . . . . . . . . . . . 38 8.7.4. NAT-Control-Definition AVP .........................37
8.7.6. NAT-External-Address AVP . . . . . . . . . . . . . . . 39 8.7.5. NAT-Internal-Address AVP ...........................38
8.7.7. Max-NAT-Bindings . . . . . . . . . . . . . . . . . . . 39 8.7.6. NAT-External-Address AVP ...........................38
8.7.8. NAT-Control-Binding-Template AVP . . . . . . . . . . . 39 8.7.7. Max-NAT-Bindings ...................................39
8.7.9. Duplicate-Session-Id AVP . . . . . . . . . . . . . . . 39 8.7.8. NAT-Control-Binding-Template AVP ...................39
8.7.10. NAT-External-Port-Style AVP . . . . . . . . . . . . . 40 8.7.9. Duplicate-Session-Id AVP ...........................39
9. Accounting Commands . . . . . . . . . . . . . . . . . . . . . 40 8.7.10. NAT-External-Port-Style AVP .......................39
9.1. NAT Control Accounting Messages . . . . . . . . . . . . . 41 9. Accounting Commands ............................................40
9.2. NAT Control Accounting AVPs . . . . . . . . . . . . . . . 41 9.1. NAT Control Accounting Messages ...........................40
9.2.1. NAT-Control-Record . . . . . . . . . . . . . . . . . . 41 9.2. NAT Control Accounting AVPs ...............................40
9.2.2. NAT-Control-Binding-Status . . . . . . . . . . . . . . 41 9.2.1. NAT-Control-Record .................................41
9.2.3. Current-NAT-Bindings . . . . . . . . . . . . . . . . . 42 9.2.2. NAT-Control-Binding-Status .........................41
10. AVP Occurrence Table . . . . . . . . . . . . . . . . . . . . . 42 9.2.3. Current-NAT-Bindings ...............................41
10.1. DNCA AVP Table for NAT Control Initial and Update 10. AVP Occurrence Tables .........................................41
Requests . . . . . . . . . . . . . . . . . . . . . . . . . 42 10.1. DNCA AVP Table for NAT Control Initial and Update
10.2. DNCA AVP Table for Session Query request . . . . . . . . . 43 Requests .................................................42
10.3. DNCA AVP Table for Accounting Message . . . . . . . . . . 44 10.2. DNCA AVP Table for Session Query Requests ................43
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44 10.3. DNCA AVP Table for Accounting Messages ...................43
11.1. Application Identifier . . . . . . . . . . . . . . . . . . 44 11. IANA Considerations ...........................................44
11.2. Command Codes . . . . . . . . . . . . . . . . . . . . . . 45 11.1. Application Identifier ...................................44
11.3. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 45 11.2. Command Codes ............................................44
11.4. Result-Code AVP Values . . . . . . . . . . . . . . . . . . 45 11.3. AVP Codes ................................................44
11.5. NC-Request-Type AVP . . . . . . . . . . . . . . . . . . . 45 11.4. Result-Code AVP Values ...................................44
11.6. NAT-External-Port-Style AVP . . . . . . . . . . . . . . . 45 11.5. NC-Request-Type AVP ......................................44
11.7. NAT-Control-Binding-Status AVP . . . . . . . . . . . . . . 45 11.6. NAT-External-Port-Style AVP ..............................45
12. Security Considerations . . . . . . . . . . . . . . . . . . . 45 11.7. NAT-Control-Binding-Status AVP ...........................45
13. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 12. Security Considerations .......................................45
13.1. DNCA Session Establishment Example . . . . . . . . . . . . 48 13. Examples ......................................................47
13.2. DNCA Session Update with Port Style Example . . . . . . . 51 13.1. DNCA Session Establishment Example .......................47
13.3. DNCA Session Query Example . . . . . . . . . . . . . . . . 52 13.2. DNCA Session Update with Port Style Example ..............50
13.4. DNCA Session Termination Example . . . . . . . . . . . . . 53 13.3. DNCA Session Query Example ...............................51
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 56 13.4. DNCA Session Termination Example .........................53
15. Change History (to be removed prior to publication as an 14. Acknowledgements ..............................................55
RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 15. References ....................................................55
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 60 15.1. Normative References .....................................55
16.1. Normative References . . . . . . . . . . . . . . . . . . . 60 15.2. Informative References ...................................56
16.2. Informative References . . . . . . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 62
1. Introduction 1. Introduction
Internet service providers deploy Network Address Translators (NATs) Internet service providers deploy Network Address Translators (NATs)
and Network Address and Port Translators (NAPTs) [RFC3022] in their and Network Address and Port Translators (NAPTs) [RFC3022] in their
networks. A key motivation for doing so is the depletion of networks. A key motivation for doing so is the depletion of
available public IPv4 addresses. This document defines a Diameter available public IPv4 addresses. This document defines a Diameter
application allowing providers to control the behavior of NAT and application allowing providers to control the behavior of NAT and
NAPT devices that implement IPv4-to-IPv4 network address and port NAPT devices that implement IPv4-to-IPv4 network address and port
translation [RFC2663] as well as stateful IPv6-to-IPv4 address family translation [RFC2663] as well as stateful IPv6-to-IPv4 address family
translation as defined in [RFC2663], [RFC6145], and [RFC6146]. The translation as defined in [RFC2663], [RFC6145], and [RFC6146]. The
use of a Diameter application allows for simple integration into the use of a Diameter application allows for simple integration into the
existing Authentication, Authorization and Accounting (AAA) existing Authentication, Authorization, and Accounting (AAA)
environment of a provider. environment of a provider.
The Diameter Network address and port translation Control Application The Diameter Network address and port translation Control Application
(DNCA) offers the following capabilities: (DNCA) offers the following capabilities:
1. Limits or defines the number of NAPT/NAT bindings made available 1. Limits or defines the number of NAPT/NAT-bindings made available
to an individual endpoint. The main motivation for restricting to an individual endpoint. The main motivation for restricting
the number of bindings on a per endpoint basis is to protect the the number of bindings on a per-endpoint basis is to protect the
service of the service provider against denial of service service of the service provider against denial-of-service (DoS)
attacks. If multiple endpoints share a single public IP address, attacks. If multiple endpoints share a single public IP address,
these endpoints can share fate. If one endpoint would (either these endpoints can share fate. If one endpoint would (either
intentionally, or due to mis-behavior, mis-configuration, mal- intentionally, or due to misbehavior, misconfiguration, malware,
ware, etc.) be able to consume all available bindings for a given etc.) be able to consume all available bindings for a given
single public IP address, service would be hampered (or might single public IP address, service would be hampered (or might
even become unavailable) for those other endpoints sharing the even become unavailable) for those other endpoints sharing the
same public IP address. The efficiency of a NAPT deployment same public IP address. The efficiency of a NAPT deployment
depends on the maximum number of bindings an endpoint could use. depends on the maximum number of bindings an endpoint could use.
Given that the typical number of bindings an endpoint uses Given that the typical number of bindings an endpoint uses
depends on the type of endpoint (e.g. a personal computer of a depends on the type of endpoint (e.g., a personal computer of a
broadband user is expected to use a higher number of bindings broadband user is expected to use a higher number of bindings
than a simple mobile phone) and a NAPT device is often shared by than a simple mobile phone) and a NAPT device is often shared by
different types of endpoints, it is desirable to actively manage different types of endpoints, it is desirable to actively manage
the maximum number of bindings. This requirement is specified in the maximum number of bindings. This requirement is specified in
REQ-3 of [I-D.ietf-behave-lsn-requirements] REQ-3 of [CGN-REQS].
2. Supports the allocation of specific NAPT/NAT bindings. Two types 2. Supports the allocation of specific NAPT/NAT-bindings. Two types
of specific bindings can be distinguished: of specific bindings can be distinguished:
* Allocation of a pre-defined NAT binding: Both the internal and * Allocation of a predefined NAT-binding: The internal and
external IP address and port pair are specified within the external IP addresses as well as the port pair are specified
request. Some deployment cases, such as access to a web- within the request. Some deployment cases, such as access to
server within a user's home network with IP address and port, a web-server within a user's home network with IP address and
benefit from statically configured bindings. port, benefit from statically configured bindings.
* Allocation of an external IP address for a given internal IP * Allocation of an external IP address for a given internal IP
address: The allocated external IP address is reported back to address: The allocated external IP address is reported back to
the requestor. In some deployment scenarios, the application the requester. In some deployment scenarios, the application
requires immediate knowledge of the allocated binding for a requires immediate knowledge of the allocated binding for a
given internal IP address but does not control the allocation given internal IP address but does not control the allocation
of the external IP address; for example, SIP-proxy server of the external IP address; for example, SIP-proxy server
deployments. deployments.
3. Defines the external address pool(s) to be used for allocating an 3. Defines the external address pool(s) to be used for allocating an
external IP address: External address pools can either be pre- external IP address: External address pools can be either pre-
assigned at the NAPT/NAT device, or specified within a request. assigned at the NAPT/NAT device or specified within a request.
If pre-assigned address pools are used, a request needs to If pre-assigned address pools are used, a request needs to
include a reference to identify the pool. Otherwise, the request include a reference to identify the pool. Otherwise, the request
contains a description of the IP address pool(s) to be used; for contains a description of the IP address pool(s) to be used, for
example, a list of IP-subnets. Such external address pools can example, a list of IP-subnets. Such external address pools can
be used to select the external IP address in NAPT/NAT bindings be used to select the external IP address in NAPT/NAT-bindings
for multiple subscribers. for multiple subscribers.
4. Generates reports and accounting records: Reports established 4. Generates reports and accounting records: Reports established
bindings for a particular endpoint. The collected information is bindings for a particular endpoint. The collected information is
used by accounting systems for statistical purposes. used by accounting systems for statistical purposes.
5. Queries and retrieves details about bindings on demand: This 5. Queries and retrieves details about bindings on demand: This
feature complements the previously mentioned accounting feature complements the previously mentioned accounting
functionality (see item 4). This feature can be used by an functionality (see item 4). This feature can be used by an
entity to find NAT-bindings belonging to one or multiple entity to find NAT-bindings belonging to one or multiple
endpoints on the NAT-device. The entity is not required to endpoints on the NAT device. The entity is not required to
create a DNCA control session to perform the query, but would create a DNCA control session to perform the query but would,
obviously still need to create a Diameter session complying to obviously, still need to create a Diameter session complying to
the security requirements. the security requirements.
6. Identifies a subscriber or endpoint on multiple network devices 6. Identifies a subscriber or endpoint on multiple network devices
(NAT/NAPT device, the AAA-server, or the Network Access Server (NAT/NAPT device, the AAA-server, or the Network Access Server
(NAS)): Endpoint identification is facilitated through a Global (NAS)): Endpoint identification is facilitated through a Global
Endpoint ID. Endpoints are identified through a single or a set Endpoint ID. Endpoints are identified through a single
of classifiers, such as IP address, Virtual Local Area Network classifier or a set of classifiers, such as IP address, Virtual
(VLAN) identifier, or interface identifier which uniquely Local Area Network (VLAN) identifier, or interface identifier
identify the traffic associated with a particular global that uniquely identify the traffic associated with a particular
endpoint. global endpoint.
With the above capabilities, DNCA qualifies as a MIDCOM protocol With the above capabilities, DNCA qualifies as a Middlebox
[RFC3303], [RFC3304], [RFC5189] for middle boxes which perform NAT. Communications (MIDCOM) protocol [RFC3303], [RFC3304], [RFC5189] for
The MIDCOM protocol evaluation [RFC4097] evaluated Diameter as a middleboxes that perform NAT. The MIDCOM protocol evaluation
candidate protocol for MIDCOM. DNCA provides the extensions to the [RFC4097] evaluated Diameter as a candidate protocol for MIDCOM.
Diameter base protocol [RFC3588] following the MIDCOM protocol DNCA provides the extensions to the Diameter base protocol [RFC6733]
requirements, such as the support of NAT-specific rule transport, following the MIDCOM protocol requirements, such as the support of
support for oddity of mapped ports, as well as support for NAT-specific rule transport, support for oddity of mapped ports, as
consecutive range port numbers. DNCA adds to the MIDCOM protocol well as support for consecutive range port numbers. DNCA adds to the
capabilities in that it allows to maintain the reference to an MIDCOM protocol capabilities in that it allows the maintenance of the
endpoint representing a user or subscriber in the control operation, reference to an endpoint representing a user or subscriber in the
enabling the control of the behavior of a NAT-device on a per control operation, enabling the control of the behavior of a NAT
endpoint basis. Following the requirements of different operators device on a per-endpoint basis. Following the requirements of
and deployments, different management protocols are employed. different operators and deployments, different management protocols
Examples include e.g. SNMP [RFC3411] and NETCONF [RFC6241] which can are employed. Examples include, for example, Simple Network
both be used for device configuration. Similarly, DNCA is Management Protocol (SNMP) [RFC3411] and Network Configuration
complementing existing MIDCOM implementations, offering a MIDCOM (NETCONF) [RFC6241], which can both be used for device configuration.
protocol option for operators with an operational environment that is Similarly, DNCA complements existing MIDCOM implementations, offering
Diameter-focused which desire to use Diameter to perform per endpoint a MIDCOM protocol option for operators with an operational
NAT control. Note that in case an operator uses multiple methods and environment that is Diameter focused that desire the use of Diameter
protocols to configure a NAT-device, such as for example command line to perform per-endpoint NAT control. Note that in case an operator
interface, SNMP, NETCONF, or PCP, along with DNCA specified in this uses multiple methods and protocols to configure a NAT device, such
document, the operator MUST ensure that the configurations performed as, for example, command line interface (CLI), SNMP, NETCONF, or Port
using the different methods and protocols do not conflict in order to Control Protocol (PCP), along with DNCA specified in this document,
ensure a proper operation of the NAT service. the operator MUST ensure that the configurations performed using the
different methods and protocols do not conflict in order to ensure a
proper operation of the NAT service.
This document is structured as follows: Section 2 lists terminology, This document is structured as follows: Section 2 lists terminology,
while Section 3 provides an introduction to DNCA and its overall while Section 3 provides an introduction to DNCA and its overall
deployment framework. Sections 4 to 8 cover DNCA specifics, with deployment framework. Sections 3.2 to 8 cover DNCA specifics, with
Section 4 describing session management, Section 5 the use of the Section 3.2 describing session management, Section 5 the use of the
Diameter base protocol, Section 6 new commands, Section 7 Attribute Diameter base protocol, Section 6 new commands, Section 8 Attribute
Value Pairs(AVPs) used, and Section 8 accounting aspects. Section 9 Value Pairs (AVPs) used, and Section 9 accounting aspects.
presents AVP occurrence tables. IANA and security considerations are Section 10 presents AVP occurrence tables. IANA and security
addressed in Sections 10 and 11. considerations are addressed in Sections 11 and 12, respectively.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Abbreviations used in this document: Abbreviations and terminology used in this document:
AAA: Authentication, Authorization, Accounting AAA: Authentication, Authorization, Accounting
DNCA: Diameter Network address and port translation Control DNCA: Diameter Network address and port translation Control
Application Application
Endpoint: Managed entity of the DNCA. An endpoint represents a Endpoint: Managed entity of the DNCA. An endpoint represents a
network element or device, associated with a subscriber, a user or network element or device, associated with a subscriber, a user,
a group of users. An endpoint is represented by a single access- or a group of users. An endpoint is represented by a single
session on a NAS. DNCA assumes a 1:1 relationship between an access-session on a NAS. DNCA assumes a 1:1 relationship between
endpoint, the access-session it represents, and the associated an endpoint, the access-session it represents, and the associated
DNCA session. DNCA session.
NAPT: Network Address and Port Translation, see also [RFC3022] NAPT: Network Address and Port Translation, see also [RFC3022].
NAT: Network Address Translation (NAT and NAPT are used in this NAT: Network Address Translation (NAT and NAPT are used in this
document interchangeably) document interchangeably)
NAT-binding or binding: Association of two IP address/port pairs NAT-binding or binding: Association of two IP address/port pairs
(with one IP address typically being private and the other one (with one IP address typically being private and the other one
public) to facilitate NAT public) to facilitate NAT
NAT binding predefined template: Is a policy template or NAT-binding predefined template: A policy template or
configuration that is predefined at the NAT-device. It may configuration that is predefined at the NAT device. It may
contain NAT-bindings, IP-address pools for allocating the external contain NAT-bindings, IP address pools for allocating the external
IP-address of a NAT-binding, the maximum number of allowed NAT- IP address of a NAT-binding, the maximum number of allowed NAT-
bindings for end-points, etc. bindings for endpoints, etc.
NAT-device: Network Address Translator or Network Address and Port NAT device: Network Address Translator or Network Address and Port
Translator: An entity performing NAT or NAPT. Translator: An entity performing NAT or NAPT.
NAT-controller: Entity controlling the behavior of a NAT-device. NAT controller: Entity controlling the behavior of a NAT device.
NAS: Network Access Server NAS: Network Access Server
NCR: NAT Control Request NCR: NAT-Control-Request
NCA: NAT Control Answer NCA: NAT-Control-Answer
NAT44: IPv4 to IPv4 network address and port translation, see NAT44: IPv4-to-IPv4 NAPT, see [RFC2663]
[RFC2663]
NAT64: IPv6 to IPv4 address family translation, see [RFC6145] and NAT64: IPv6-to-IPv4 address family translation, see [RFC6145] and
[RFC6146] [RFC6146]
PPP: Point-to-Point Protocol [RFC1661] PPP: Point-to-Point Protocol [RFC1661]
3. Deployment Framework 3. Deployment Framework
3.1. Deployment Scenario 3.1. Deployment Scenario
Figure 1 shows a typical network deployment for IPv4-Internet access. Figure 1 shows a typical network deployment for IPv4 Internet access.
A user's IPv4 host (i.e. endpoint) gains access to the Internet A user's IPv4 host (i.e., endpoint) gains access to the Internet
though a NAS, which facilitates the authentication of the endpoint though a NAS, which facilitates the authentication of the endpoint
and configures the endpoints's connection according to the and configures the endpoint's connection according to the
authorization and configuration data received from the AAA-server authorization and configuration data received from the AAA-server
upon successful authentication. Public IPv4 addresses are used upon successful authentication. Public IPv4 addresses are used
throughout the network. DNCA manages an endpoint that represents a throughout the network. DNCA manages an endpoint that represents a
network element or device or IPv4 host, associated with a subscriber, network element or device or an IPv4 host, associated with a
a user or a group of users. An endpoint is represented by a single subscriber, a user or a group of users. An endpoint is represented
access-session on a NAS. DNCA assumes a 1:1 relationship between an by a single access-session on a NAS. DNCA assumes a 1:1:1
endpoint, the access-session it represents, and the associated DNCA relationship between an endpoint, the access-session it represents,
session. and the associated DNCA session.
+---------+ +---------+
| | | |
| AAA | | AAA |
| | | |
+---------+ +---------+
| |
| |
| |
| |
+---------+ +---------+ +----------+ +---------+ +---------+ +----------+
| IPv4 | | | | IPv4 | | IPv4 | | | | IPv4 |
| Host |----------| NAS |-------------| Internet | | Host |----------| NAS |-------------| Internet |
| | | | | | | | | | | |
+---------+ +---------+ +----------+ +---------+ +---------+ +----------+
<-------------------- Public IPv4 ----------------------> <-------------------- Public IPv4 ---------------------->
Figure 1: Typical network deployment for internet access Figure 1: Typical Network Deployment for Internet Access
Figure 2 depicts the deployment scenario where a service provider Figure 2 depicts the deployment scenario where a service provider
places a NAT between the host and the public Internet. The objective places a NAT between the host and the public Internet. The objective
is to provide the customer with connectivity to the public IPv4 is to provide the customer with connectivity to the public IPv4
Internet. The NAT-device performs network address and port (and Internet. The NAT device performs network address and port (and
optionally address family) translation, depending on whether the optionally address family) translation, depending on whether the
access network uses private IPv4 addresses or public IPv6 addresses, access network uses private IPv4 addresses or public IPv6 addresses
to public IPv4 addresses. Note that there may be more than one NAS, to public IPv4 addresses. Note that there may be more than one NAS,
NAT-device, or AAA-entity in a deployment, although the figures only NAT device, or AAA-entity in a deployment, although the figures only
depict one entity each for clarity. depict one entity each for clarity.
If the NAT-device would be put in place without any endpoint If the NAT device would be put in place without any endpoint
awareness, the service offerings of the service provider could be awareness, the service offerings of the service provider could be
impacted as detailed in [I-D.ietf-behave-lsn-requirements]. This impacted as detailed in [CGN-REQS]. This includes cases like the
includes cases like: following:
o Provisioning static NAT bindings for particular endpoints o Provisioning static NAT-bindings for particular endpoints
o Using different public IP address pools for different set of o Using different public IP address pools for a different set of
endpoints (for example, residential or business customers) endpoints (for example, residential or business customers)
o Reporting allocated bindings on a per endpoint basis o Reporting allocated bindings on a per-endpoint basis
o Integrate control of the NAT-device into the already existing per o Integrate control of the NAT device into the already existing per-
endpoint management infrastructure of the service provider endpoint management infrastructure of the service provider
+---------+ +---------+
| | | |
| AAA | | AAA |
| | | |
+---------+ +---------+
| |
| |
| |
| |
+--------+ +---------+ +--------+ +----------+ +--------+ +---------+ +--------+ +----------+
| IPv4 |----| |----| NAT- |----| IPv4- | | IPv4 |----| |----| NAT- |----| IPv4 |
| Host | | NAS | | device | | Internet | | Host | | NAS | | device | | Internet |
| | | | | | | | | | | | | | | |
+--------+ +---------+ +--------+ +----------+ +--------+ +---------+ +--------+ +----------+
For NAT44 deployments (IPv4 host): For NAT44 deployments (IPv4 host):
<----- Private IPv4 ----------><--- Public IPv4 ---> <----- Private IPv4 ----------><--- Public IPv4 --->
For NAT64 deployments (IPv6 host): For NAT64 deployments (IPv6 host):
<----- Public IPv6 ----------><--- Public IPv4 ---> <----- Public IPv6 ----------><--- Public IPv4 --->
Figure 2: Access network deployment with NAT Figure 2: Access Network Deployment with NAT
Figure 2 shows a typical deployment for IPv4-Internet access Figure 2 shows a typical deployment for IPv4 Internet access
involving a NAT-device within the service provider network. The involving a NAT device within the service provider network. The
figure describes two scenarios: One where an IPv4-host (with a figure describes two scenarios: one where an IPv4 host (with a
private IPv4 address) accesses the IPv4-Internet, as well as one private IPv4 address) accesses the IPv4 Internet, as well as one
where an IPv6-host accesses the IPv4-Internet. where an IPv6-host accesses the IPv4 Internet.
3.2. Diameter NAPT Control Application Overview 3.2. Diameter NAPT Control Application Overview
DNCA runs between two DNCA Diameter peers. One DNCA Diameter peer DNCA runs between two DNCA Diameter peers. One DNCA Diameter peer
resides within the NAT-device, the other DNCA Diameter peer resides resides within the NAT device, the other DNCA Diameter peer resides
within a NAT-controller (discussed in Section 3.3). DNCA allows per within a NAT controller (discussed in Section 3.3). DNCA allows per-
endpoint control and management of NAT within the NAT-device. Based endpoint control and management of NAT within the NAT device. Based
on Diameter, DNCA integrates well with the suite of Diameter on Diameter, DNCA integrates well with the suite of Diameter
applications deployed for per endpoint authentication, authorization, applications deployed for per-endpoint authentication, authorization,
accounting, and policy control in service provider networks. accounting, and policy control in service provider networks.
DNCA offers: DNCA offers:
o Request and answer commands to control the allowed number of NAT o Request and answer commands to control the allowed number of NAT-
bindings per endpoint to request the allocation of specific bindings per endpoint, to request the allocation of specific
bindings for an endpoint, to define the address pool to be used bindings for an endpoint, to define the address pool to be used
for an endpoint. for an endpoint.
o Provides per endpoint reporting of the allocated NAT bindings. o Per-endpoint reporting of the allocated NAT-bindings.
o Provides unique identification of an endpoint on NAT-device, AAA- o Unique identification of an endpoint on a NAT device, AAA-server,
server and NAS, to simplify correlation of accounting data and NAS to simplify correlation of accounting data streams.
streams.
DNCA allows controlling the behavior of a NAT-device on a per DNCA allows controlling the behavior of a NAT device on a per-
endpoint basis during initial session establishment and at later endpoint basis during initial session establishment and at later
stages by providing an update procedure for already established stages by providing an update procedure for already established
sessions. Using DNCA, per endpoint NAT binding information can be sessions. Using DNCA, per-endpoint NAT-binding information can be
retrieved either using accounting mechanisms or through an explicit retrieved using either accounting mechanisms or an explicit session
session query to the NAT. query to the NAT.
3.3. Deployment Scenarios For DNCA 3.3. Deployment Scenarios for DNCA
DNCA can be deployed in different ways. DNCA supports deployments DNCA can be deployed in different ways. DNCA supports deployments
with "n" NAT-controllers and "m" NAT-devices, with n and m equal to with "n" NAT controllers and "m" NAT devices, with n and m equal to
or greater than 1. From a DNCA perspective an operator should ensure or greater than 1. From a DNCA perspective, an operator should
that the session representing a particular endpoint is atomic. Any ensure that the session representing a particular endpoint is atomic.
deployment MUST ensure that for any given endpoint only a single DNCA Any deployment MUST ensure that, for any given endpoint, only a
NAT-controller and is active at any point in time. This is to ensure single DNCA NAT controller and is active at any point in time. This
that NAT-devices controlled by multiple NAT-controllers do not is to ensure that NAT devices controlled by multiple NAT controllers
receive conflicting control requests for a particular endpoint, or do not receive conflicting control requests for a particular endpoint
would be unclear which NAT-controller to send accounting information or that they would not be unclear about to which NAT controller to
to. Operational considerations MAY require an operator to use send accounting information. Operational considerations MAY require
alternate control mechanisms or protocols such as SNMP or manual an operator to use alternate control mechanisms or protocols such as
configuration via a Command-Line-Interface to apply per-endpoint NAT- SNMP or manual configuration via a CLI to apply per-endpoint NAT-
specific configuration, like for example static NAT-bindings. For specific configuration, for example, static NAT-bindings. For these
these cases, the NAT-device MUST allow the operator to configure a cases, the NAT device MUST allow the operator to configure a policy
policy how configuration conflicts are resolved. Such a policy could on how configuration conflicts are resolved. Such a policy could
for example specify that manually configured NAT-bindings using the specify, for example, that manually configured NAT-bindings using the
Command-Line-Interface always take precedence over those configured CLI always take precedence over those configured using DNCA.
using DNCA.
Two common deployment scenarios are outlined in Figure 3 ("integrated Two common deployment scenarios are outlined in Figure 3 ("Integrated
deployment") and Figure 4 ("autonomous deployment"). Per the note Deployment") and Figure 4 ("Autonomous Deployment"). Per the note
above, multiple instances of NAT-controllers and NAT-devices could be above, multiple instances of NAT controllers and NAT devices could be
deployed. The figures only show single instances for reasons of deployed. The figures only show single instances for reasons of
clarity. The two shown scenarios differ in which entity fulfills the clarity. The two shown scenarios differ in which entity fulfills the
role of the NAT-controller. Within the figures (C) denotes the role of the NAT controller. Within the figures, (C) denotes the
network element performing the role of the NAT-controller. network element performing the role of the NAT controller.
The integrated deployment approach hides the existence of the NAT- The integrated deployment approach hides the existence of the NAT
device from external servers, such as the AAA-server. It is suited device from external servers, such as the AAA-server. It is suited
for environments where minimal changes to the existing AAA deployment for environments where minimal changes to the existing AAA deployment
are desired. The NAS and the NAT-device are Diameter peers are desired. The NAS and the NAT device are Diameter peers
supporting the DNCA. The Diameter peer within the NAS, performing supporting the DNCA. The Diameter peer within the NAS, performing
the role of the NAT-controller, initiates and manages sessions with the role of the NAT controller, initiates and manages sessions with
the NAT-device, exchanges NAT specific configuration information and the NAT device, exchanges NAT-specific configuration information, and
handles reporting and accounting information. The NAS receives handles reporting and accounting information. The NAS receives
reporting and accounting information from the NAT-device. With this reporting and accounting information from the NAT device. With this
information, the NAS can provide a single accounting record for the information, the NAS can provide a single accounting record for the
endpoint. A system correlating the accounting information received endpoint. A system correlating the accounting information received
from the NAS and NAT-device would not be needed. from the NAS and NAT device would not be needed.
An example network attachment for an integrated NAT deployment can be An example network attachment for an integrated NAT deployment can be
described as follows: An endpoint connects to the network, with the described as follows: an endpoint connects to the network, with the
NAS being the point of attachment. After successful authentication, NAS being the point of attachment. After successful authentication,
the NAS receives endpoint related authorization data from the AAA- the NAS receives endpoint-related authorization data from the AAA-
server. A portion of the authorization data applies to per endpoint server. A portion of the authorization data applies to per-endpoint
configuration on the NAS itself, another portion describes configuration on the NAS itself, another portion describes
authorization and configuration information for NAT control aimed at authorization and configuration information for NAT control aimed at
the NAT-device. The NAS initiates a DNCA session to the NAT-device the NAT device. The NAS initiates a DNCA session to the NAT device
and sends relevant authorization and configuration information for and sends relevant authorization and configuration information for
the particular endpoint to the NAT-device. This can comprise NAT- the particular endpoint to the NAT device. This can comprise NAT-
bindings, which have to be pre-established for the endpoint, or bindings, which have to be pre-established for the endpoint, or
management related configuration, such as the maximum number of NAT- management-related configuration, such as the maximum number of NAT-
bindings allowed for the endpoint. The NAT-device sends its per bindings allowed for the endpoint. The NAT device sends its per-
endpoint accounting information to the NAS, which aggregates the endpoint accounting information to the NAS, which aggregates the
accounting information received from the NAT-device with its local accounting information received from the NAT device with its local
accounting information for the endpoint into a single accounting accounting information for the endpoint into a single accounting
stream towards the AAA-server. stream towards the AAA-server.
+---------+ +---------+
| | | |
| AAA | | AAA |
| | | |
+---------+ +---------+
| |
| |
| |
+--------+ +---------+ +--------+ +----------+ +--------+ +---------+ +--------+ +----------+
| | | (C) | | | | | | | | (C) | | | | |
| Host |----| NAS |----| NAT- |----| IPv4- | | Host |----| NAS |----| NAT- |----| IPv4 |
| | | | | device | | Internet | | | | | | device | | Internet |
+--------+ +---------+ +--------+ +----------+ +--------+ +---------+ +--------+ +----------+
For NAT44 deployments (IPv4 host): For NAT44 deployments (IPv4 host):
<----- Private IPv4 ----------><--- Public IPv4 ---> <----- Private IPv4 ----------><--- Public IPv4 --->
For NAT64 deployments (IPv6 host): For NAT64 deployments (IPv6 host):
<----- Public IPv6 ----------><--- Public IPv4 ---> <----- Public IPv6 ----------><--- Public IPv4 --->
Figure 3: NAT control deployment: Integrated deployment Figure 3: NAT Control Deployment: Integrated Deployment
Figure 3 shows examples of integrated deployments. The figure Figure 3 shows examples of integrated deployments. It illustrates
describes two scenarios: One where an IPv4-host (with a private IPv4 two scenarios: one where an IPv4 host (with a private IPv4 address)
address) accesses the IPv4-Internet, as well as one where an IPv6- accesses the IPv4 Internet and another where an IPv6 host accesses
host accesses the IPv4-Internet. the IPv4 Internet.
The autonomous deployment approach decouples endpoint management on The autonomous deployment approach decouples endpoint management on
the NAS and NAT-device. In the autonomous deployment approach, the the NAS and NAT device. In the autonomous deployment approach, the
AAA-system and the NAT-device are the Diameter peers running the AAA-system and the NAT device are the Diameter peers running the
DNCA. The AAA-system also serves as NAT-controller. It manages the DNCA. The AAA-system also serves as NAT controller. It manages the
connection to the NAT-device, controls the per endpoint connection to the NAT device, controls the per-endpoint
configuration, and also receives accounting and reporting information configuration, and receives accounting and reporting information from
from the NAT-device. Different from the integrated deployment the NAT device. Different from the integrated deployment scenario,
scenario, the autonomous deployment scenario does not "hide" the the autonomous deployment scenario does not "hide" the existence of
existence of the NAT-device from the AAA infrastructure. Here two the NAT device from the AAA infrastructure. Here, two accounting
accounting streams are received by the AAA-server for one particular streams are received by the AAA-server for one particular endpoint:
endpoint, one from the NAS, and one from the NAT-device. one from the NAS and one from the NAT device.
+---------+ +---------+
| (C) | | (C) |
| AAA |--------- | AAA |---------
| | | | | |
+---------+ | +---------+ |
| | | |
| | | |
| | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +---------+ +----------+
skipping to change at page 13, line 38 skipping to change at page 12, line 37
| IPv6 |----| NAS |----| NAT- |----| Internet | | IPv6 |----| NAS |----| NAT- |----| Internet |
| Host | | | | device | | | | Host | | | | device | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +---------+ +----------+
For NAT44 deployments (IPv4 host): For NAT44 deployments (IPv4 host):
<----- Private IPv4 ----------><--- Public IPv4 ---> <----- Private IPv4 ----------><--- Public IPv4 --->
For NAT64 deployments (IPv6 host): For NAT64 deployments (IPv6 host):
<----- Public IPv6 ----------><--- Public IPv4 ---> <----- Public IPv6 ----------><--- Public IPv4 --->
Figure 4: NAT control deployment: Autonomous deployment Figure 4: NAT Control Deployment: Autonomous Deployment
Figure 4 shows examples of autonomous deployments. The figure Figure 4 shows examples of autonomous deployments. It illustrates
describes two scenarios: One where an IPv4-host (with a private IPv4 two scenarios: one where an IPv4 host (with a private IPv4 address)
address) accesses the IPv4-Internet, as well as one where an IPv6- accesses the IPv4 Internet and another where an IPv6 host accesses
host accesses the IPv4-Internet. the IPv4 Internet.
4. DNCA Session Establishment and Management 4. DNCA Session Establishment and Management
Note that this section forward references some of the commands and Note that from this section on, there are references to some of the
AVPs defined for DNCA. Please refer to Section 6 and Section 8 for commands and AVPs defined for DNCA. Please refer to Sections 6 and 8
details. DNCA runs between a Diameter peer residing in a NAT- for details. DNCA runs between a Diameter peer residing in a NAT
controller and a Diameter peer residing in a NAT-device. Note that, controller and a Diameter peer residing in a NAT device. Note that,
per what was already mentioned above, each DNCA session between per what was already mentioned above, each DNCA session between
Diameter peers in a NAT-controller and a NAT-device represents a Diameter peers in a NAT controller and a NAT device represents a
single endpoint, with an endpoint being either a network element, a single endpoint, with an endpoint being either a network element, a
device or an IPv4 host associated with a subscriber, a user, or a device, or an IPv4 host associated with a subscriber, a user, or a
group of users. The Diameter peer within the NAT-controller is group of users. The Diameter peer within the NAT controller is
always the control requesting entity: It initiates, updates, or always the control-requesting entity: it initiates, updates, or
terminates the sessions. Sessions are initiated when the NAT- terminates the sessions. Sessions are initiated when the NAT
controller learns about a new endpoint (i.e., host) that requires a controller learns about a new endpoint (i.e., host) that requires a
NAT service. This could for example be due to the entity hosting the NAT service. This could be due to, for example, the entity hosting
NAT-controller receiving authentication, authorization, or accounting the NAT controller receiving authentication, authorization, or
requests for or from the endpoint. Alternate methods that could accounting requests for or from the endpoint. Alternate methods that
trigger session setup include local configuration, receipt of a could trigger session setup include local configuration, receipt of a
packet from a formerly unknown IP-address, etc. packet from a formerly unknown IP address, etc.
4.1. Session Establishment 4.1. Session Establishment
The DNCA Diameter peer within the NAT-controller establishes a The DNCA Diameter peer within the NAT controller establishes a
session with the DNCA Diameter peer within the NAT-device to control session with the DNCA Diameter peer within the NAT device to control
the behavior of the NAT function within the NAT-device. During the behavior of the NAT function within the NAT device. During
session establishment, the DNCA Diameter peer within the NAT- session establishment, the DNCA Diameter peer within the NAT
controller passes along configuration information to DNCA Diameter controller passes along configuration information to the DNCA
peer within the NAT-device. The session configuration information Diameter peer within the NAT device. The session configuration
comprises the maximum number of bindings allowed for the endpoint information comprises the maximum number of bindings allowed for the
associated with this session, a set of pre-defined NAT bindings to be endpoint associated with this session, a set of predefined NAT-
established for this endpoint, or a description of the address pool, bindings to be established for this endpoint, or a description of the
that external addresses are to be allocated from. address pool, from which external addresses are to be allocated.
The DNCA Diameter peer within the NAT-controller generates a NAT- The DNCA Diameter peer within the NAT controller generates a NAT-
Control Request (NCR) message to the DNCA Diameter peer within the Control-Request (NCR) message to the DNCA Diameter peer within the
NAT-device with NC-Request-Type AVP set to INITIAL_REQUEST to NAT device with the NC-Request-Type AVP set to INITIAL_REQUEST to
initiate a Diameter NAT control session. On receipt of a NCR the initiate a Diameter NAT control session. On receipt of an NCR, the
DNCA Diameter peer within the NAT-device sets up a new session for DNCA Diameter peer within the NAT device sets up a new session for
the endpoint associated with the endpoint classifier(s) contained in the endpoint associated with the endpoint classifier(s) contained in
the NCR. The DNCA Diameter peer within the NAT-device notifies its the NCR. The DNCA Diameter peer within the NAT device notifies its
DNCA Diameter peer within the NAT-controller about successful session DNCA Diameter peer within the NAT controller about successful session
setup using a NAT-Control Answer (NCA) message with Result-Code set setup using a NAT-Control-Answer (NCA) message with the Result-Code
to DIAMETER_SUCCESS. Figure 5 shows the initial protocol interaction set to DIAMETER_SUCCESS. Figure 5 shows the initial protocol
between the two DNCA Diameter peers. interaction between the two DNCA Diameter peers.
The initial NAT-Control-Request MAY contain configuration information The initial NAT-Control-Request MAY contain configuration information
for the session, which specifies the behavior of the NAT-device for for the session, which specifies the behavior of the NAT device for
the session. The configuration information that MAY be included, the session. The configuration information that MAY be included,
comprises: comprises:
o A list of NAT bindings, which should be pre-allocated for the o A list of NAT-bindings, which should be pre-allocated for the
session; for example, in case an endpoint requires a fixed session; for example, in case an endpoint requires a fixed
external IP-address/port pair for an application. external IP address/port pair for an application.
o The maximum number of NAT-bindings allowed for an endpoint. o The maximum number of NAT-bindings allowed for an endpoint.
o A description of the external IP-address pool(s) to be used for o A description of the external IP address pool(s) to be used for
the session. the session.
o A reference to a NAT Binding Predefined template on the NAT- o A reference to a NAT-binding Predefined template on the NAT
device, which is applied to the session. Such a NAT Binding device, which is applied to the session. Such a NAT-binding
Predefined template on the NAT-device may contain, for example, Predefined template on the NAT device may contain, for example,
the name of the IP-address pool that external IP-addresses should the name of the IP address pool from which external IP addresses
be allocated from, the maximum number of bindings permitted for should be allocated, the maximum number of bindings permitted for
the endpoint, etc. the endpoint, etc.
In certain cases, the NAT-device may not be able to perform the tasks In certain cases, the NAT device may not be able to perform the tasks
requested within the NCR. These include the following: requested within the NCR. These include the following:
o If a DNCA Diameter peer within the NAT-device receives a NCR from o If a DNCA Diameter peer within the NAT device receives an NCR from
a DNCA Diameter peer within a NAT-controller with NC-Request-Type a DNCA Diameter peer within a NAT controller with the NC-Request-
AVP set to INITIAL_REQUEST that identifies an already existing Type AVP set to INITIAL_REQUEST that identifies an already
session; that is endpoint identifier match an already existing existing session, that is, the endpoint identifier matches an
session, the DNCA Diameter peer within the NAT-device MUST return already existing session, the DNCA Diameter peer within the NAT
an NCA with Result-Code set to SESSION_EXISTS, and provide the device MUST return an NCA with the Result-Code set to
Session-Id of the existing session in the Duplicate-Session-Id SESSION_EXISTS and provide the Session-Id of the existing session
AVP. in the Duplicate-Session-Id AVP.
o If a DNCA Diameter peer within the NAT-device receives a NCR from o If a DNCA Diameter peer within the NAT device receives an NCR from
a DNCA Diameter peer within a NAT-controller with NC-Request-Type a DNCA Diameter peer within a NAT controller with the NC-Request-
AVP set to INITIAL_REQUEST that matches more than one of the Type AVP set to INITIAL_REQUEST that matches more than one of the
already existing sessions; that is, DNCA Diameter peer and already existing sessions, that is, the DNCA Diameter peer and
endpoint identifier match already existing sessions, the DNCA endpoint identifier match already existing sessions, the DNCA
Diameter peer within the NAT-device MUST return an NCA with Diameter peer within the NAT device MUST return an NCA with the
Result-Code set to INSUFFICIENT-CLASSIFIERS. In case a DNCA Result-Code set to INSUFFICIENT-CLASSIFIERS. In case a DNCA
Diameter peer receives a NCA that reports Insufficient- Diameter peer receives an NCA that reports Insufficient-
Classifiers, it MAY choose to retry establishing a new session Classifiers, it MAY choose to retry establishing a new session
using additional or more specific classifiers. using additional or more specific classifiers.
o If the NCR contains a NAT Binding predefined template not defined o If the NCR contains a NAT-binding Predefined template not defined
on the NAT-device, the DNCA Diameter peer within the NAT-device on the NAT device, the DNCA Diameter peer within the NAT device
MUST return an NCA with Result-Code AVP set to MUST return an NCA with the Result-Code AVP set to
UNKNOWN_BINDING_TEMPLATE_NAME. UNKNOWN_BINDING_TEMPLATE_NAME.
o In case the NAT-device is unable to establish all of the bindings o In case the NAT device is unable to establish all of the bindings
requested in the NCR, the DNCA Diameter peer MUST return an NCA requested in the NCR, the DNCA Diameter peer MUST return an NCA
with Result-Code set to BINDING_FAILURE. A DNCA Diameter peer with the Result-Code set to BINDING_FAILURE. A DNCA Diameter peer
within a NAT-device MUST treat a NCR as an atomic operation; hence within a NAT device MUST treat an NCR as an atomic operation;
none of the requested bindings will be established by the NAT- hence, none of the requested bindings will be established by the
device. Either all requested actions within a NCR MUST be NAT device. Either all requested actions within an NCR MUST be
completed successfully, or the entire request fails. completed successfully or the entire request fails.
o If a NAT-device cannot conform to a request to set the maximum o If a NAT device cannot conform to a request to set the maximum
number of NAT bindings allowed for a session, the DNCA Diameter number of NAT-bindings allowed for a session, the DNCA Diameter
peer in the NAT-device MUST return an NCA with Result-Code AVP set peer in the NAT device MUST return an NCA with the Result-Code AVP
to MAX_BINDINGS_SET_FAILURE. Such a condition can for example set to MAX_BINDINGS_SET_FAILURE. Such a condition can, for
occur if the operator specified the maximum number of NAT bindings example, occur if the operator specified the maximum number of
through another mechanism, which per the operator's policy, takes NAT-bindings through another mechanism, which, per the operator's
precedence over DNCA. policy, takes precedence over DNCA.
o If a NAT-device does not have sufficient resources to process a o If a NAT device does not have sufficient resources to process a
request, the DNCA Diameter peer MUST return an NCA with Result- request, the DNCA Diameter peer MUST return an NCA with the
Code set to RESOURCE_FAILURE. Result-Code set to RESOURCE_FAILURE.
o In case Max-NAT-Bindings, NAT-Control-Definition as well as NAT- o In the case where Max-NAT-Bindings, NAT-Control-Definition, and
Control-Binding-Template are included in the NCR, and the values NAT-Control-Binding-Template are included in the NCR, and the
in Max-NAT-Bindings and NAT-Control-Definition contradict those values in Max-NAT-Bindings and NAT-Control-Definition contradict
specified in the pre-provisioned template on the NAT-device which those specified in the pre-provisioned template on the NAT device
NAT-Control-Binding-Template references, Max-NAT-Bindings and NAT- that NAT-Control-Binding-Template references, Max-NAT-Bindings and
Control-Definition MUST override the values specified in the NAT-Control-Definition MUST override the values specified in the
template that NAT-Control-Binding-Template refers to. template to which NAT-Control-Binding-Template refers.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer) NAT controller (DNCA Diameter peer) NAT device (DNCA Diameter peer)
| | | |
| | | |
| | | |
Trigger | Trigger |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| | | |
| | | |
| | | |
| | | |
| If Able to comply | If able to comply
| with Request then | with request, then
| Create session state | create session state
| | | |
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| | | |
| | | |
Figure 5: Initial NAT control request and session establishment Figure 5: Initial NAT-Control-Request and Session Establishment
Note: The DNCA Diameter peer within the NAT-device creates session Note: The DNCA Diameter peer within the NAT device creates session
state only if it is able to comply with the NCR. On success it will state only if it is able to comply with the NCR. On success, it will
reply with an NCA with Result-Code set to DIAMETER_SUCCESS. reply with an NCA with the Result-Code set to DIAMETER_SUCCESS.
4.2. Session Update 4.2. Session Update
Session update is performed if the NAT-controller desires to change A session update is performed if the NAT controller desires to change
the behavior of the NAT-device for an existing session. Session the behavior of the NAT device for an existing session. A session
update could be used, for example, to change the number of allowed update could be used, for example, to change the number of allowed
bindings for a particular session, or establish or remove a pre- bindings for a particular session or establish or remove a predefined
defined binding. binding.
The DNCA Diameter peer within the NAT-controller generates a NCR The DNCA Diameter peer within the NAT controller generates an NCR
message to the DNCA Diameter peer within the NAT-device with NC- message to the DNCA Diameter peer within the NAT device with the NC-
Request-Type AVP set to UPDATE_REQUEST upon receiving a trigger Request-Type AVP set to UPDATE_REQUEST upon receiving a trigger
signal. If the session is updated successfully, the DNCA Diameter signal. If the session is updated successfully, the DNCA Diameter
peer within the NAT-device notifies the DNCA Diameter peer within the peer within the NAT device notifies the DNCA Diameter peer within the
NAT-controller about the successful session update using a NAT- NAT controller about the successful session update using a NAT-
Control Answer (NCA) message with Result-Code set to Control-Answer (NCA) message with the Result-Code set to
DIAMETER_SUCCESS.Figure 6 shows the protocol interaction between the DIAMETER_SUCCESS. Figure 6 shows the protocol interaction between
two DNCA Diameter peers. the two DNCA Diameter peers.
In certain cases, the NAT-device may not be able to perform the tasks In certain cases, the NAT device may not be able to perform the tasks
requested within the NCR. These include the following: requested within the NCR. These include the following:
o If DNCA Diameter peer within a NAT-device receives an NCR update o If a DNCA Diameter peer within a NAT device receives an NCR update
or query request for a non-existent session, it MUST set Result- or query request for a non-existent session, it MUST set the
Code in the answer to DIAMETER_UNKNOWN_SESSION_ID. Result-Code in the answer to DIAMETER_UNKNOWN_SESSION_ID.
o If the NCR contains a NAT Binding Predefined template not defined o If the NCR contains a NAT-binding Predefined template not defined
on the NAT-device, an NCA with Result-Code AVP set to on the NAT device, an NCA with the Result-Code AVP set to
UNKNOWN_BINDING_TEMPLATE_NAME MUST be returned. UNKNOWN_BINDING_TEMPLATE_NAME MUST be returned.
o If the NAT-device cannot establish the requested binding because o If the NAT device cannot establish the requested binding because
the maximum number of allowed bindings has been reached for the the maximum number of allowed bindings has been reached for the
endpoint classifier, an NCA with Result-Code AVP set to endpoint classifier, an NCA with the Result-Code AVP set to
MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT MUST be returned to the DNCA MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT MUST be returned to the DNCA
Diameter peer. Diameter peer.
o If the NAT-device cannot establish some or all of the bindings o If the NAT device cannot establish some or all of the bindings
requested in an NCR, but has not yet reached the maximum number of requested in an NCR, but has not yet reached the maximum number of
allowed bindings for the endpoint, an NCA with Result-Code set to allowed bindings for the endpoint, an NCA with the Result-Code set
BINDING_FAILURE MUST be returned. As already noted, the DNCA to BINDING_FAILURE MUST be returned. As already noted, the DNCA
Diameter peer in a NAT-device MUST treat an NCR as an atomic Diameter peer in a NAT device MUST treat an NCR as an atomic
operation. Hence none of the requested bindings will be operation. Hence, none of the requested bindings will be
established by the NAT-device in case of failure. Actions established by the NAT device in case of failure. Actions
requested within a NCR are either all successful or all fail. requested within an NCR are either all successful or all fail.
o If the NAT-device cannot conform to a request to set the maximum o If the NAT device cannot conform to a request to set the maximum
number of bindings allowed for a session as specified by the Max- number of bindings allowed for a session as specified by the Max-
NAT-Bindings, the DNCA Diameter peer in the NAT-device MUST return NAT-Bindings, the DNCA Diameter peer in the NAT device MUST return
an NCA with Result-Code AVP set to MAX_BINDINGS_SET_FAILURE. an NCA with the Result-Code AVP set to MAX_BINDINGS_SET_FAILURE.
o If the NAT-device does not have sufficient resources to process a o If the NAT device does not have sufficient resources to process a
request, an NCA with Result-Code set to RESOURCE_FAILURE MUST be request, an NCA with the Result-Code set to RESOURCE_FAILURE MUST
returned. be returned.
o If an NCR changes the maximum number of NAT-bindings allowed for o If an NCR changes the maximum number of NAT-bindings allowed for
the endpoint defined through an earlier NCR, the new value MUST the endpoint defined through an earlier NCR, the new value MUST
override any previously defined limit on the maximum number of NAT override any previously defined limit on the maximum number of
bindings set through DNCA. Note that prior to overwriting an NAT-bindings set through the DNCA. Note that, prior to
existing value, the NAT-device MUST check whether the overwrite overwriting an existing value, the NAT device MUST check whether
action conforms to the locally configured policy. Deployment the overwrite action conforms to the locally configured policy.
dependent, an existing value could have been set by a protocol or Deployment dependent, an existing value could have been set by a
mechanism different from DNCA and with higher priority. In which protocol or mechanism different from DNCA and with higher
case, the NAT-device will refuse the change and the DNCA Diameter priority. In which case, the NAT device will refuse the change
peer in the NAT-device MUST return an NCA with Result-Code AVP set and the DNCA Diameter peer in the NAT device MUST return an NCA
to MAX_BINDINGS_SET_FAILURE. It depends on the implementation of with the Result-Code AVP set to MAX_BINDINGS_SET_FAILURE. It
the NAT-device on how the NAT-device copes with a case where the depends on the implementation of the NAT device on how the NAT
new value is lower than the actual number of allocated bindings. device copes with a case where the new value is lower than the
The NAT-device SHOULD refrain from enforcing the new limit actual number of allocated bindings. The NAT device SHOULD
immediately (that is, actively remove bindings), but rather refrain from enforcing the new limit immediately (that is,
disallows the establishment of new bindings until the current actively remove bindings), but rather disallows the establishment
number of bindings is lower than the newly established maximum of new bindings until the current number of bindings is lower than
number of allowed bindings. the newly established maximum number of allowed bindings.
o If an NCR specifies a new NAT Binding Predefined template on the o If an NCR specifies a new NAT-binding Predefined template on the
NAT-device, the NAT Binding Predefined template overrides any NAT device, the NAT-binding Predefined template overrides any
previously defined rule for the session. Existing NAT-bindings previously defined rule for the session. Existing NAT-bindings
SHOULD NOT be impacted by the change of templates. SHOULD NOT be impacted by the change of templates.
o In case Max-NAT-Binding, NAT-Control-Definition as well as NAT- o In case Max-NAT-Bindings, NAT-Control-Definition, and NAT-Control-
Control-Binding-Template are included in the NCR, and the values Binding-Template are included in the NCR, and the values in Max-
in Max-NAT-Bindings and NAT-Control-Definition contradict those NAT-Bindings and NAT-Control-Definition contradict those specified
specified in the pre-provisioned template on the NAT-device which in the pre-provisioned template on the NAT device that NAT-
NAT-Control-Binding-Template references, Max-NAT-Bindings and NAT- Control-Binding-Template references, Max-NAT-Bindings and NAT-
Control-Definition MUST override the values specified in the Control-Definition MUST override the values specified in the
template that the NAT-Control-Binding-Template refers to. template to which the NAT-Control-Binding-Template refers.
Note: Already established bindings for the session SHOULD NOT be Note: Already established bindings for the session SHOULD NOT be
affected in case the tasks requested within the NCR cannot be affected in case the tasks requested within the NCR cannot be
completed. completed.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer) NAT controller (DNCA Diameter peer) NAT device (DNCA Diameter peer)
| | | |
| | | |
| | | |
Change of session | Change of session |
attributes | attributes |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| | | |
| | | |
| If able to comply | If able to comply
| with the request: | with the request:
| Update session state | update session state
| | | |
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| | | |
Figure 6: NAT control request for session update Figure 6: NAT-Control-Request for Session Update
4.3. Session and Binding Query 4.3. Session and Binding Query
A Session and NAT-binding query MAY be used by the DNCA Diameter peer A session and NAT-binding query MAY be used by the DNCA Diameter peer
within the NAT-controller to either retrieve information on the within the NAT controller either to retrieve information on the
current bindings for a particular session at the NAT-device or current bindings for a particular session at the NAT device or to
discover the session identifier for a particular external IP address/ discover the session identifier for a particular external IP address/
port pair. port pair.
A DNCA Diameter peer within the NAT-controller starts a session query A DNCA Diameter peer within the NAT controller starts a session query
by sending an NCR message with NC-Request-Type AVP set to by sending an NCR message with NC-Request-Type AVP set to
QUERY_REQUEST. Figure 7 shows the protocol interaction between the QUERY_REQUEST. Figure 7 shows the protocol interaction between the
DNCA Diameter peers. DNCA Diameter peers.
Two types of query requests exist. The first type of query request Two types of query requests exist. The first type of query request
uses the session ID as input parameter to the query. It is to allow uses the Session-Id as input parameter to the query. It is to allow
the DNCA Diameter peer within the NAT-controller to retrieve the the DNCA Diameter peer within the NAT controller to retrieve the
current set of bindings for a specific session. The second type of current set of bindings for a specific session. The second type of
query request is used to retrieve the session identifiers, along with query request is used to retrieve the session identifiers, along with
the associated bindings, matching a criteria. This enables the DNCA the associated bindings, matching a criteria. This enables the DNCA
Diameter peer within the NAT-controller to find those sessions, which Diameter peer within the NAT controller to find those sessions, which
utilize a specific external or internal IP-address. utilize a specific external or internal IP address.
1. Request a list of currently allocated NAT bindings for a 1. Request a list of currently allocated NAT-bindings for a
particular session: On receiving a NCR, the NAT-device SHOULD particular session: On receiving an NCR, the NAT device SHOULD
look up the session information for the session ID contained in look up the session information for the Session-Id contained in
the NCR, and report all currently active NAT-bindings for the the NCR and report all currently active NAT-bindings for the
session using an NCA message with Result-Code set to session using an NCA message with the Result-Code set to
DIAMETER_SUCCESS. In this case the NCR MUST NOT contain a NAT- DIAMETER_SUCCESS. In this case, the NCR MUST NOT contain a NAT-
Control-Definition AVP. Each NAT-binding is reported in a NAT- Control-Definition AVP. Each NAT-binding is reported in a NAT-
Control-Definition AVP. In case the session ID is unknown, the Control-Definition AVP. In case the Session-Id is unknown, the
DNCA Diameter peer within the NAT-device MUST return an NCA DNCA Diameter peer within the NAT device MUST return an NCA
message with Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. message with the Result-Code set to DIAMETER_UNKNOWN_SESSION_ID.
2. Retrieve session IDs and bindings for internal IP-address or one 2. Retrieve Session-Ids and bindings for internal IP address or one
or multiple external IP-address/port pairs: If the DNCA Diameter or multiple external IP address/port pairs: If the DNCA Diameter
peer within the NAT-controller wishes to retrieve the session peer within the NAT controller wishes to retrieve the Session-
ID(s) for internal IP-address or one or multiple external IP- Id(s) for an internal IP address or one or multiple external IP
address/port pairs, it MUST include the internal IP-address as address/port pairs, it MUST include the internal IP address as
part of Framed-IP-Address or external IP-address/port pair(s) as part of the Framed-IP-Address AVP or external IP address/port
part of the NAT-External-Address AVP of the NCR. The external pair(s) as part of the NAT-External-Address AVP of the NCR. The
IP-address/port pair(s) are pre-known to the controller via external IP address/port pair(s) are known in advance by the
configuration, AAA interactions, or other means. The session ID controller via configuration, AAA interactions, or other means.
is not included in the NCR or the NCA for this type of a query. The Session-Id is not included in the NCR or the NCA for this
The DNCA Diameter peer within the NAT-device SHOULD report the type of a query. The DNCA Diameter peer within the NAT device
NAT-bindings and associated session IDs corresponding to the SHOULD report the NAT-bindings and associated Session-Ids
internal IP-address or external IP-address/port pairs in an NCA corresponding to the internal IP address or external IP address/
message using one or multiple instances of the NAT-Control- port pairs in an NCA message using one or multiple instances of
Definition AVP. The Result-Code is set to DIAMETER_SUCCESS. In the NAT-Control-Definition AVP. The Result-Code is set to
case an external IP-address/port pair has no associated existing DIAMETER_SUCCESS. In case an external IP address/port pair has
NAT-binding, the NAT-Control-Definition AVP contained in the no associated existing NAT-binding, the NAT-Control-Definition
reply just contains the NAT-External-Address AVP. AVP contained in the reply just contains the NAT-External-Address
AVP.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer) NAT controller (DNCA Diameter peer) NAT device (DNCA Diameter peer)
| | | |
| | | |
| | | |
DNCA Session Established | DNCA Session Established |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| | | |
| | | |
| | | |
| | | |
| Look up corresponding session | Look up corresponding session
| and associated NAT-bindings | and associated NAT-bindings
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| | | |
| | | |
| | | |
Figure 7: Session query
Figure 7: Session Query
4.4. Session Termination 4.4. Session Termination
Similar to session initiation, session tear down MUST be initiated by Similar to session initiation, session tear down MUST be initiated by
the DNCA Diameter peer within the NAT-controller. The DNCA Diameter the DNCA Diameter peer within the NAT controller. The DNCA Diameter
peer sends a Session Terminate Request (STR) message to its peer peer sends a Session-Termination-Request (STR) message to its peer
within the NAT-device upon receiving a trigger signal. The source of within the NAT device upon receiving a trigger signal. The source of
the trigger signal is outside the scope of this document. As part of the trigger signal is outside the scope of this document. As part of
STR message processing the DNCA Diameter peer within the NAT-device STR-message processing, the DNCA Diameter peer within the NAT device
MAY send an accounting stop record reporting all bindings. All the MAY send an accounting stop record reporting all bindings. All the
NAT-bindings belonging to the session MUST be removed and the session NAT-bindings belonging to the session MUST be removed, and the
state MUST be cleaned up. The DNCA Diameter peer within the NAT- session state MUST be cleaned up. The DNCA Diameter peer within the
device MUST notify its DNCA Diameter peer in the NAT-controller about NAT device MUST notify its DNCA Diameter peer in the NAT controller
successful session termination using a Session Terminate Answer (STA) about successful session termination using a Session-Termination-
message with Result-Code set to DIAMETER_SUCCESS. Figure 8 shows the Answer (STA) message with Result-Code set to DIAMETER_SUCCESS.
protocol interaction between the two DNCA Diameter peers. Figure 8 shows the protocol interaction between the two DNCA Diameter
peers.
If a DNCA Diameter peer within a NAT-device receives a STR and fails If a DNCA Diameter peer within a NAT device receives an STR and fails
to find a matching session, the DNCA Diameter peer MUST return a STA to find a matching session, the DNCA Diameter peer MUST return an STA
with Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. with the Result-Code set to DIAMETER_UNKNOWN_SESSION_ID.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer) NAT controller (DNCA Diameter peer) NAT device (DNCA Diameter peer)
| | | |
| | | |
Trigger | Trigger |
| | | |
| STR | | STR |
|------------------------------------------->| |------------------------------------------->|
| | | |
| | | |
| | | |
| | | |
skipping to change at page 22, line 35 skipping to change at page 21, line 35
| Terminate session / | Terminate session /
| Remove session state | Remove session state
| | | |
| | | |
| | | |
| STA | | STA |
|<-------------------------------------------| |<-------------------------------------------|
| | | |
| | | |
Figure 8: Terminate NAT control session Figure 8: Terminate NAT Control Session
4.5. Session Abort 4.5. Session Abort
An Abort-Session-Request (ASR) message is sent from the DNCA Diameter An Abort-Session-Request (ASR) message is sent from the DNCA Diameter
peer within the NAT-device to the DNCA Diameter peer within the NAT- peer within the NAT device to the DNCA Diameter peer within the NAT
controller when it is unable to maintain a session due to resource controller when it is unable to maintain a session due to resource
limitations. The DNCA Diameter peer within the NAT-controller MUST limitations. The DNCA Diameter peer within the NAT controller MUST
acknowledge successful session abort using a Abort Session Answer acknowledge a successful session abort using an Abort-Session-Answer
(ASA) message with Result-Code set to DIAMETER_SUCCESS. Figure 9 (ASA) message with the Result-Code set to DIAMETER_SUCCESS. Figure 9
shows the protocol interaction between the DNCA Diameter peers. The shows the protocol interaction between the DNCA Diameter peers. The
DNCA Diameter peers will start a session termination procedure as DNCA Diameter peers will start a session termination procedure as
described in Section 4.4 following an ASA with Result-Code set to described in Section 4.4 following an ASA with the Result-Code set to
DIAMETER_SUCCESS. DIAMETER_SUCCESS.
If the DNCA Diameter peer within a NAT-controller receives an ASR but If the DNCA Diameter peer within a NAT controller receives an ASR but
fails to find a matching session, it MUST return an ASA with Result- fails to find a matching session, it MUST return an ASA with the
Code set to DIAMETER_UNKNOWN_SESSION_ID. If the DNCA Diameter peer Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. If the DNCA Diameter
within the NAT-controller is unable to comply with the ASR for any peer within the NAT controller is unable to comply with the ASR for
other reason, an ASA with Result-Code set to any other reason, an ASA with the Result-Code set to
DIAMETER_UNABLE_TO_COMPLY MUST be returned. DIAMETER_UNABLE_TO_COMPLY MUST be returned.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer) NAT controller (DNCA Diameter peer) NAT device (DNCA Diameter peer)
| | | |
| | | |
| Trigger | Trigger
| | | |
| ASR | | ASR |
|<-------------------------------------------| |<-------------------------------------------|
| | | |
| | | |
| | | |
| ASA | | ASA |
|------------------------------------------->| |------------------------------------------->|
| | | |
| | | |
| | | |
| On successful ASA | | On successful ASA |
|<------Session Termination Procedure------->| |<------Session Termination Procedure------->|
Figure 9: Abort NAT control session Figure 9: Abort NAT Control Session
4.6. Failure cases of the DNCA Diameter peers 4.6. Failure Cases of the DNCA Diameter Peers
This document does not specify the behavior in case the NAT-device This document does not specify the behavior in case the NAT device
and NAT-controller, or their respective DNCA Diameter peers are out and NAT controller, or their respective DNCA Diameter peers, are out
of sync or lose state. This could happen for example if one of the of sync or lose state. This could happen, for example, if one of the
entities restarts, in case of a (temporary) loss of network entities restarts, in case of a (temporary) loss of network
connectivity etc. Example failure cases include the following: connectivity, etc. Example failure cases include the following:
o NAT-controller and the DNCA Diameter peer within the NAT- o NAT controller and the DNCA Diameter peer within the NAT
controller lose state (e.g., due to a restart). In this case, controller lose state (e.g., due to a restart). In this case:
* the DNCA Diameter peer within the NAT-device MAY receive an NCR * the DNCA Diameter peer within the NAT device MAY receive an NCR
with NC-Request-Type AVP set to INITIAL_REQUEST that matches an with the NC-Request-Type AVP set to INITIAL_REQUEST that
existing session of the DNCA Diameter peer within the NAT- matches an existing session of the DNCA Diameter peer within
device. The DNCA Diameter peer within the NAT-device MUST the NAT device. The DNCA Diameter peer within the NAT device
return Result-Code that contains Duplicate-Session-Id AVP to MUST return a Result-Code that contains a Duplicate-Session-Id
report the Session-ID of the existing session. The DNCA AVP to report the Session-Id of the existing session. The DNCA
Diameter peer within the NAT-controller MAY send an explicit Diameter peer within the NAT controller MAY send an explicit
Session Terminate Request (STR) for the older session, which Session-Termination-Request (STR) for the older session, which
was lost. was lost.
* a DNCA Diameter peer MAY receive accounting records for a * a DNCA Diameter peer MAY receive accounting records for a
session that does not exist. The DNCA Diameter peer sends an session that does not exist. The DNCA Diameter peer sends an
accounting answer with Result-Code set to accounting answer with the Result-Code set to
DIAMETER_UNKNOWN_SESSION_ID in response. On receiving the DIAMETER_UNKNOWN_SESSION_ID in response. On receiving the
response, the DNCA Diameter peer SHOULD clear the session and response, the DNCA Diameter peer SHOULD clear the session and
remove associated session state. remove associated session state.
o NAT-device and the DNCA Diameter peer within NAT-device lose o The NAT device and the DNCA Diameter peer within NAT device lose
state. In such a case, the DNCA Diameter peer MAY receive a NCR state. In such a case, the DNCA Diameter peer MAY receive an NCR
with NC-Request-Type AVP set to UPDATE_REQUEST for a non-existent with the NC-Request-Type AVP set to UPDATE_REQUEST for a non-
session. The DNCA Diameter peer MUST return an NCA with Result- existent session. The DNCA Diameter peer MUST return an NCA with
Code set to DIAMETER_UNKNOWN_SESSION_ID. When DNCA application the Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. When a DNCA
within NAT-controller receives this NCA within Result-Code set to application within a NAT controller receives this NCA with the
DIAMETER_UNKNOWN_SESSION_ID, it MAY try to reestablish DNCA Result-Code set to DIAMETER_UNKNOWN_SESSION_ID, it MAY try to re-
session or disconnect corresponding access session. establish DNCA session or disconnect corresponding access session.
o The DNCA Diameter peer within the NAT-controller is unreachable, o The DNCA Diameter peer within the NAT controller is unreachable,
for example detected by Diameter device watchdog messages (as for example, it is detected by Diameter device watchdog messages
defined in Section 5.5 of [RFC3588]), or accounting requests from (as defined in Section 5.5 of [RFC6733]) or accounting requests
the DNCA Diameter peer fail to get a response, NAT-bindings and from the DNCA Diameter peer fail to get a response, NAT-bindings
NAT-device state pertaining to that session MUST be cleaned up and NAT device state pertaining to that session MUST be cleaned up
after a grace period that is configurable on the NAT-device. The after a grace period that is configurable on the NAT device. The
grace period can be configured as zero or higher, depending on grace period can be configured as zero or higher, depending on
operator preference. operator preference.
o The DNCA Diameter peer within the NAT-device is unreachable or o The DNCA Diameter peer within the NAT device is unreachable or
down and NCR fails to get a response. Handling of this case down and the NCR fails to get a response. Handling of this case
depends on the actual service offering of the service provider. depends on the actual service offering of the service provider.
The service provider could for example choose to stop offering The service provider could, for example, choose to stop offering
connectivity service. connectivity service.
o A discussion of the mechanisms how a NAT-device cleans up state in o A discussion of the mechanisms used for a NAT device to clean up
case the DNCA Diameter peer within the NAT-device crashes is state in case the DNCA Diameter peer within the NAT device crashes
outside the scope of this document. Implementers of NAT-devices is outside the scope of this document. Implementers of NAT
could choose from a variety of options such as coupling the state devices could choose from a variety of options such as coupling
(e.g. NAT bindings) to timers which require periodic refresh, or the state (e.g., NAT-bindings) to timers that require periodic
time out otherwise, operating system watchdogs for applications, refresh, or time out otherwise, operating system watchdogs for
etc. applications, etc.
5. Use of the Diameter Base Protocol 5. Use of the Diameter Base Protocol
The Diameter Base Protocol defined by [RFC3588] applies with the The Diameter base protocol [RFC6733] applies with the clarifications
clarifications listed in the present specification. listed in the present specification.
5.1. Securing Diameter Messages 5.1. Securing Diameter Messages
For secure transport of Diameter messages, the recommendations in For secure transport of Diameter messages, the recommendations in
[RFC3588] apply. [RFC6733] apply.
DNCA Diameter peers SHOULD verify their identity during the DNCA Diameter peers SHOULD verify their identity during the
Capabilities Exchange Request procedure. Capabilities Exchange Request procedure.
A DNCA Diameter peer within the NAT-device SHOULD verify that a DNCA A DNCA Diameter peer within the NAT device SHOULD verify that a DNCA
Diameter peer that issues a NCR command is allowed to do so based on: Diameter peer that issues an NCR command is allowed to do so based
on:
o The identity of the DNCA Diameter peer o The identity of the DNCA Diameter peer
o The type of NCR Command o The type of NCR Command
o The content of the NCR Command o The content of the NCR Command
o Any combination of the above o Any combination of the above
5.2. Accounting Functionality 5.2. Accounting Functionality
Accounting functionality (accounting session state machine, related Accounting functionality (the accounting session state machine,
command codes and AVPs) is defined in Section 9 below. related Command Codes and AVPs) is defined in Section 9.
5.3. Use of Sessions 5.3. Use of Sessions
Each DNCA session MUST have a globally unique Session-ID as defined Each DNCA session MUST have a globally unique Session-Id, as defined
in [RFC3588], which MUST NOT be changed during the lifetime of a DNCA in [RFC6733], which MUST NOT be changed during the lifetime of the
session. The Diameter Session-ID serves as the global endpoint DNCA session. The Diameter Session-Id serves as the global endpoint
identifier. The DNCA Diameter peers maintain state associated with identifier. The DNCA Diameter peers maintain state associated with
the Session-ID. This globally unique Session-ID is used for the Session-Id. This globally unique Session-Id is used for
updating, accounting, and terminating the session. A DNCA session updating, accounting, and terminating the session. A DNCA session
MUST NOT have more than one outstanding request at any given instant. MUST NOT have more than one outstanding request at any given time. A
A DNCA Diameter peer sends an Abort-Session-Request as defined in DNCA Diameter peer sends an Abort-Session-Request as defined in
[RFC3588] if it is unable to maintain sessions due to resource [RFC6733] if it is unable to maintain sessions due to resource
limitation. limitation.
5.4. Routing Considerations 5.4. Routing Considerations
It is assumed that the DNCA Diameter peer within a NAT-controller It is assumed that the DNCA Diameter peer within a NAT controller
knows the DiameterIdentity of the Diameter peer within a NAT-device knows the DiameterIdentity of the Diameter peer within a NAT device
for a given endpoint. Both the Destination-Realm and Destination- for a given endpoint. Both the Destination-Realm and Destination-
Host AVPs are present in the request from a DNCA Diameter peer within Host AVPs are present in the request from a DNCA Diameter peer within
a NAT-controller to a DNCA Diameter peer within a NAT-device. a NAT controller to a DNCA Diameter peer within a NAT device.
5.5. Advertising Application Support 5.5. Advertising Application Support
Diameter nodes conforming to this specification MUST advertise Diameter nodes conforming to this specification MUST advertise
support for DNCA by including the value of TBD.APP-ID in the Auth- support for DNCA by including the value of 12 in the Auth-
Application-Id of the Capabilities-Exchange-Request and Capabilities- Application-Id of the Capabilities-Exchange-Request and Capabilities-
Exchange-Answer command[RFC3588]. Exchange-Answer commands [RFC6733].
6. DNCA Commands 6. DNCA Commands
The following commands are used to establish, maintain and query NAT- The following commands are used to establish, maintain, and query
bindings. NAT-bindings.
6.1. NAT-Control Request (NCR) Command 6.1. NAT-Control-Request (NCR) Command
The NAT-Control Request (NCR) command, indicated by the command field The NAT-Control-Request (NCR) command, indicated by the command field
set to TBD.COM-CODE and the "R" bit set in the Command Flags field, set to 330 and the 'R' bit set in the Command Flags field, is sent
is sent from the DNCA Diameter peer within the NAT-controller to the from the DNCA Diameter peer within the NAT controller to the DNCA
DNCA Diameter peer within the NAT-device in order to install NAT- Diameter peer within the NAT device in order to install NAT-bindings.
bindings.
User-Name, Logical-Access-Id, Physical-Access-ID, Framed-IP-Address, User-Name, Logical-Access-Id, Physical-Access-ID, Framed-IP-Address,
Framed-IPv6-Prefix, Framed-Interface-Id, EGRESS-VLANID, NAS-Port-ID, Framed-IPv6-Prefix, Framed-Interface-Id, EGRESS-VLANID, NAS-Port-ID,
Address-Realm, Calling-Station-ID AVPs serve as identifiers for the Address-Realm, and Calling-Station-ID AVPs serve as identifiers for
endpoint. the endpoint.
Message format: Message format:
< NC-Request > ::= < Diameter Header: TBD.COM-CODE, REQ, PXY> < NC-Request > ::= < Diameter Header: 330, REQ, PXY>
{ Auth-Application-Id } { Auth-Application-Id }
{ Origin-Host } { Origin-Host }
{ Origin-Realm } { Origin-Realm }
{ Destination-Realm } { Destination-Realm }
{ Destination-Host } { Destination-Host }
{ NC-Request-Type } { NC-Request-Type }
[ Session-Id ] [ Session-Id ]
[ Origin-State-Id ] [ Origin-State-Id ]
*1 [ NAT-Control-Remove ] *1 [ NAT-Control-Remove ]
*1 [ NAT-Control-Install ] *1 [ NAT-Control-Install ]
skipping to change at page 27, line 5 skipping to change at page 26, line 5
[ Framed-IPv6-Prefix ] [ Framed-IPv6-Prefix ]
[ Framed-Interface-Id ] [ Framed-Interface-Id ]
[ EGRESS-VLANID] [ EGRESS-VLANID]
[ NAS-Port-ID] [ NAS-Port-ID]
[ Address-Realm ] [ Address-Realm ]
[ Calling-Station-ID ] [ Calling-Station-ID ]
* [ Proxy-Info ] * [ Proxy-Info ]
* [ Route-Record ] * [ Route-Record ]
* [ AVP ] * [ AVP ]
6.2. NAT-Control Answer (NCA) Command 6.2. NAT-Control-Answer (NCA) Command
The NAT-Control-Answer (NCA) command, indicated by the Command-Code The NAT-Control-Answer (NCA) command, indicated by the Command Code
field set to TBD.COM-CODE and the "R" bit cleared in the Command field set to 330 and the 'R' bit cleared in the Command Flags field,
Flags field, is sent by the DNCA Diameter peer within the NAT-device is sent by the DNCA Diameter peer within the NAT device in response
in response to NAT-Control-Request command. to the NAT-Control-Request command.
Message format: Message format:
<NC-Answer> ::= < Diameter Header: TBD.COM-CODE, PXY > <NC-Answer> ::= < Diameter Header: 330, PXY >
{ Origin-Host } { Origin-Host }
{ Origin-Realm } { Origin-Realm }
{ Result-Code } { Result-Code }
[ Session-Id ] [ Session-Id ]
[ NC-Request-Type ] [ NC-Request-Type ]
* [ NAT-Control-Definition ] * [ NAT-Control-Definition ]
[ Current-NAT-Bindings ] [ Current-NAT-Bindings ]
[ Origin-State-Id ] [ Origin-State-Id ]
[ Error-Message ] [ Error-Message ]
[ Error-Reporting-Host ] [ Error-Reporting-Host ]
* [ Failed-AVP ] * [ Failed-AVP ]
* [ Proxy-Info ] * [ Proxy-Info ]
[ Duplicate-Session-ID ] [ Duplicate-Session-Id ]
* [ Redirect-Host] * [ Redirect-Host]
[ Redirect-Host-Usage ] [ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ] [ Redirect-Max-Cache-Time ]
* [ Proxy-Info ] * [ Proxy-Info ]
* [ Route-Record ] * [ Route-Record ]
* [ Failed-AVP ] * [ Failed-AVP ]
* [ AVP ] * [ AVP ]
7. NAT Control Application Session State Machine 7. NAT Control Application Session State Machine
This section contains a set of finite state machines, representing This section contains a set of finite state machines, representing
the life cycle of a DNCA session, which MUST be observed by all the life cycle of a DNCA session, which MUST be observed by all
implementations of the DNCA Diameter application. The DNCA Diameter implementations of the DNCA Diameter application. The DNCA Diameter
peers are stateful and the state machine maintained is similar to the peers are stateful and the state machine maintained is similar to the
stateful Client and Server authorization state machine described in stateful client and server authorization state machine described in
[RFC3588]. When a session is moved to the Idle state, any resources [RFC6733]. When a session is moved to the Idle state, any resources
that were allocated for the particular session must be released. Any that were allocated for the particular session must be released. Any
event not listed in the state machines MUST be considered as an error event not listed in the state machines MUST be considered an error
condition, and an answer, if applicable, MUST be returned to the condition, and an answer, if applicable, MUST be returned to the
originator of the message. originator of the message.
In the state table, the event 'Failure to send NCR' means that the In the state table, the event "Failure to send NCR" means that the
DNCA Diameter peer within the NAT-controller is unable to send the DNCA Diameter peer within the NAT controller is unable to send the
NCR command to the desired destination. This could be due to the NCR command to the desired destination. This could be due to the
peer being down, or due to the peer sending back the transient peer being down or due to the peer sending back the transient failure
failure or temporary protocol error notification DIAMETER_TOO_BUSY or or temporary protocol error notification DIAMETER_TOO_BUSY or
DIAMETER_LOOP_DETECTED in the Result-Code AVP of an NCA. DIAMETER_LOOP_DETECTED in the Result-Code AVP of an NCA.
In the state table "FAILED NCA" means that the DNCA Diameter peer In the state table, "FAILED NCA" means that the DNCA Diameter peer
within the NAT-device was not able to honor the corresponding NCR. within the NAT device was not able to honor the corresponding NCR.
This can happen due to any transient and permanent error at the NAT- This can happen due to any transient or permanent error at the NAT
device or its associated DNCA Diameter peer within indicated by the device or its associated DNCA Diameter peer within indicated by the
following error Result-Code values: RESOURCE_FAILURE, following error Result-Code values: RESOURCE_FAILURE,
UNKNOWN_BINDING_TEMPLATE_NAME, MAX_BINDINGS_SET_FAILURE, UNKNOWN_BINDING_TEMPLATE_NAME, MAX_BINDINGS_SET_FAILURE,
BINDING_FAILURE, MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT, BINDING_FAILURE, MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT,
SESSION_EXISTS, INSUFFICIENT_CLASSIFIERS. SESSION_EXISTS, INSUFFICIENT_CLASSIFIERS.
The following state machine is observed by a DNCA Diameter peer The following state machine is observed by a DNCA Diameter peer
within a NAT-controller. The state machine description uses the term within a NAT controller. The state machine description uses the term
"access session" to describe the connectivity service offered to the "access session" to describe the connectivity service offered to the
endpoint or host. "Access session" should not be confused with the endpoint or host. "Access session" should not be confused with the
Diameter session ID. Diameter session.
DNCA Diameter peer within a NAT-controller DNCA Diameter peer within a NAT controller
State Event Action New State State Event Action New State
------------------------------------------------------------- -------------------------------------------------------------
Idle New endpoint detected that Send Pending Idle New endpoint detected that Send Pending
requires NAT Control NCR requires NAT control NCR
Initial Initial
Request Request
Idle ASR Received Send ASA Idle Idle ASR received Send ASA Idle
for unknown session with for unknown session with
Result-Code Result-Code
= UNKNOWN_ = UNKNOWN_
SESSION_ID SESSION_ID
Pending Successful NCA Setup Open Pending Successful NCA Setup Open
received complete received complete
Pending Successful NCA Send STR Discon Pending Successful NCA Send STR Discon
received received,
but peer unable to provide but peer unable to provide
service service
Pending Error processing successful Send STR Discon Pending Error processing successful Send STR Discon
NCA NCA
Pending Failed Clean up Idle Pending Failed Clean up Idle
NCA received NCA received
Open NAT control Send Open Open NAT control Send Open
update required NCR Update update required NCR update
Request request
Open Successful Open Open Successful Open
NCA received NCA received
Open Failed Clean up Idle Open Failed Clean up Idle
NCA received NCA received
Open Access session end detected Send STR Discon Open Access session end detected Send STR Discon
Open ASR Received, Send ASA Discon Open ASR received, Send ASA Discon
access session will be with access session will be with
terminated Result-Code terminated Result-Code
= SUCCESS, = SUCCESS,
Send STR Send STR
Open ASR Received, Send ASA Open Open ASR received, Send ASA Open
access session will not with access session will not with
be terminated Result-Code be terminated Result-Code
!= SUCCESS != SUCCESS
Discon ASR Received Send ASA Idle Discon ASR Received Send ASA Idle
Discon STA Received Discon. Idle Discon STA Received Discon. Idle
endpoint endpoint
The following state machine is observed by a DNCA Diameter peer The following state machine is observed by a DNCA Diameter peer
within a NAT-device. within a NAT device.
DNCA Diameter peer within a NAT-device DNCA Diameter peer within a NAT device
State Event Action New State State Event Action New State
------------------------------------------------------------- -------------------------------------------------------------
Idle NCR Query request Send Idle Idle NCR query request Send Idle
received, and successful received, and successful
able to provide requested NCA able to provide requested NCA
NAT Binding report NAT-binding report
Idle NCR received Send Open Idle NCR received Send Open
and able to successful and able to successful
provide requested NCA provide requested NCA
NAT control service NAT control service
Idle NCR request Send Idle Idle NCR request Send Idle
received, and failed received, and failed
unable to provide requested NCA unable to provide requested NCA
NAT control service NAT control service
Open NCR request Send Open Open NCR request Send Open
received, and successful received, and successful
able to provide requested NCA able to provide requested NCA
NAT control service NAT control service
Open NCR request Send Idle Open NCR request Send Idle
received, and failed received, and failed
unable to provide requested NCA, unable to provide requested NCA,
NAT control service Clean up NAT control service Clean up
Open Unable to continue Send ASR Discon Open Unable to continue Send ASR Discon
providing requested providing requested
NAT control service NAT control service
Open Unplanned loss of session/ Clean up Idle Open Unplanned loss of session/ Clean up Idle
connection to DNCA Diameter connection to DNCA Diameter
peer in NAT controller peer in NAT controller
detected (e.g. due to Diameter detected (e.g., due to Diameter
watchdog notification) watchdog notification)
Discon Failure to send ASR Wait, Discon Discon Failure to send ASR Wait, Discon
resend ASR resend ASR
Discon ASR successfully sent and Clean up Idle Discon ASR successfully sent and Clean up Idle
ASA Received with Result-Code ASA received with Result-Code
Not ASA Received None No change Not ASA received None No change
Discon Discon
Any STR Received Send STA, Idle Any STR received Send STA, Idle
Clean up Clean up
8. DNCA AVPs 8. DNCA AVPs
8.1. Reused Base Protocol AVPs 8.1. Reused Base Protocol AVPs
The following table describes the AVPs reused from Diameter Base The following table describes the AVPs reused from the Diameter base
Protocol [RFC3588]; their AVP Code values, types, and possible flag protocol [RFC6733]; their AVP Code values, types, and possible flag
values; and whether the AVP MAY be encrypted. The [RFC3588] values and whether the AVP MAY be encrypted. [RFC6733] specifies the
specifies the AVP Flag rules for AVPs in section 4.5. The Diameter AVP Flag rules for AVPs in Section 4.5. The Diameter AVP rules are
AVP rules are defined in the [RFC3588], section 4. defined in [RFC6733], Section 4.
+---------+ +---------+
| AVP | | AVP |
| Flag | | Flag |
| rules | | rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP | | | | | AVP | | | |
| Attribute Name Code Data Type |MUST |MAY| Encr | | Attribute Name Code Data Type |MUST |MAY| Encr |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|Acct-Interim-Interval 85 Unsigned32 | M | P | Y | |Acct-Interim-Interval 85 Unsigned32 | M | P | Y |
skipping to change at page 31, line 29 skipping to change at page 30, line 29
|Failed-AVP 279 Grouped | M | P | N | |Failed-AVP 279 Grouped | M | P | N |
|Origin-Host 264 DiamIdent | M | P | N | |Origin-Host 264 DiamIdent | M | P | N |
|Origin-Realm 296 DiamIdent | M | P | N | |Origin-Realm 296 DiamIdent | M | P | N |
|Origin-State-Id 278 Unsigned32 | M | P | N | |Origin-State-Id 278 Unsigned32 | M | P | N |
|Proxy-Info 284 Grouped | M | P | N | |Proxy-Info 284 Grouped | M | P | N |
|Result-Code 268 Unsigned32 | M | P | N | |Result-Code 268 Unsigned32 | M | P | N |
|Route-Record 282 DiamIdent | M | | N | |Route-Record 282 DiamIdent | M | | N |
|Session-Id 263 UTF8String | M | P | Y | |Session-Id 263 UTF8String | M | P | Y |
|User-Name 1 UTF8String | M | P | Y | |User-Name 1 UTF8String | M | P | Y |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
Table 1: DIAMETER AVPs used from Diameter base Table 1: DIAMETER AVPs from the Diameter Base Protocol
The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to
Diameter applications. The value of the Auth-Application-Id for the Diameter applications. The value of the Auth-Application-Id for the
Diameter NAT Control Application is TBD.APP-ID. Please refer to Diameter NAT Control Application is 12. Please refer to [RFC6733]
[RFC3588] for the definition of the Diameter AVP flag rules and the for the definition of the Diameter AVP flag rules and the associated
associated abbreviations used in the table. abbreviations used in the table.
8.2. Additional Result-Code AVP Values 8.2. Additional Result-Code AVP Values
This section defines new values for the Result-Code AVP that SHALL be This section defines new values for the Result-Code AVP that SHALL be
supported by all Diameter implementations that conform to the present supported by all Diameter implementations that conform to the present
document. document.
8.2.1. Success 8.2.1. Success
No new Result-Code AVP value is defined within this category. No new Result-Code AVP value is defined within this category.
8.2.2. Transient Failures 8.2.2. Transient Failures
Result-Code AVP values that fall within the transient failures Result-Code AVP values that fall within the transient failures
category are those used to inform a peer that the request could not category are those used to inform a peer that the request could not
be satisfied at the time that it was received. The request may be be satisfied at the time that it was received. The request may be
able to be satisfied in the future. able to be satisfied in the future.
The following new values of the Result-Code AVP are defined: The following new values of the Result-Code AVP are defined:
RESOURCE_FAILURE (TBD.RCX) RESOURCE_FAILURE (4014)
The DNCA Diameter peer within the NAT-device indicates that the The DNCA Diameter peer within the NAT device indicates that the
binding could not be installed or a new session could not be binding could not be installed or a new session could not be
created due to resource shortage. created due to resource shortage.
8.2.3. Permanent Failures 8.2.3. Permanent Failures
The Result-Code AVP values, which fall within the permanent failures The Result-Code AVP values, which fall within the permanent failures
category are used to inform the peer that the request failed, and category are used to inform the peer that the request failed and
should not be attempted again. The request may be able to be should not be attempted again. The request may be able to be
satisfied in the future. satisfied in the future.
The following new values of the Result-Code AVP are defined: The following new values of the Result-Code AVP are defined:
UNKNOWN_BINDING_TEMPLATE_NAME (TBD.RCX) UNKNOWN_BINDING_TEMPLATE_NAME (5042)
The DNCA Diameter peer within the NAT-device indicates that the The DNCA Diameter peer within the NAT device indicates that the
binding could not be installed or a new session could not be binding could not be installed or a new session could not be
created because the specified NAT-Control-Binding-Template AVP, created because the specified NAT-Control-Binding-Template AVP,
that refers to a predefined policy template in the NAT-device, which refers to a predefined policy template in the NAT device,
is unknown. is unknown.
BINDING_FAILURE (TBD.RCX) BINDING_FAILURE (5043)
The DNCA Diameter peer within the NAT-device indicates that the The DNCA Diameter peer within the NAT device indicates that the
requested binding(s) could not be installed. For example: requested binding(s) could not be installed. For example,
Requested ports are already in use. Requested ports are already in use.
MAX_BINDINGS_SET_FAILURE (TBD.RCX) MAX_BINDINGS_SET_FAILURE (5044)
The DNCA Diameter peer within the NAT-device indicates that it The DNCA Diameter peer within the NAT device indicates that it
failed to conform to a request to configure the maximum number failed to conform to a request to configure the maximum number
of bindings for a session. For example: An operator defined of bindings for a session. For example, an operator defined
the maximum number of bindings on the NAT-device using a method the maximum number of bindings on the NAT device using a method
or protocol which takes precendence over DNCA. or protocol that takes precedence over DNCA.
MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT (TBD.RCX) MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT (5045)
The DNCA Diameter peer within the NAT-device denies the request The DNCA Diameter peer within the NAT device denies the request
because the maximum number of allowed bindings has been reached because the maximum number of allowed bindings has been reached
for the specified endpoint classifier. for the specified endpoint classifier.
SESSION_EXISTS (TBD.RCX) SESSION_EXISTS (5046)
The DNCA Diameter peer within the NAT-device denies request to
initialize a new session, if it already has a DNCA session that The DNCA Diameter peer within the NAT device denies a request
uses the same set of classifiers as indicated by the DNCA to initialize a new session, if it already has a DNCA session
Diameter peer within the NAT-controller in the new session that uses the same set of classifiers as indicated by the DNCA
Diameter peer within the NAT controller in the new session
initialization request. initialization request.
INSUFFICIENT_CLASSIFIERS (TBD.RCX) INSUFFICIENT_CLASSIFIERS (5047)
The DNCA Diameter peer within the NAT-device requests to The DNCA Diameter peer within the NAT device requests to
initialize a new session, if the classifiers in the request initialize a new session, if the classifiers in the request
match more than one of the existing sessions on the DNCA match more than one of the existing sessions on the DNCA
Diameter peer within the NAT-device. Diameter peer within the NAT device.
8.3. Reused NASREQ Diameter Application AVPs 8.3. Reused NASREQ Diameter Application AVPs
The following table describes the AVPs reused from the Diameter The following table describes the AVPs reused from the Diameter
Network Access Server Application [RFC4005]; their AVP Code values, Network Access Server Application [RFC4005]; their AVP Code values,
types, and possible flag values; and whether the AVP MAY be types, and possible flag values; and whether the AVP MAY be
encrypted. The [RFC3588] specifies the AVP Flag rules for AVPs in encrypted. The [RFC6733] specifies the AVP Flag rules for AVPs in
section 4.5. The Diameter AVP rules are defined in the [RFC3588], Section 4.5. The Diameter AVP rules are defined in the [RFC6733],
section 4. Section 4.
+---------------------+ +---------------------+
| AVP Flag rules | | AVP Flag Rules |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
| | AVP | | | |SHLD| MUST| | | | AVP | | | |SHLD| MUST| |
| Attribute Name | Code | Value Type|MUST| MAY | NOT| NOT|Encr| | Attribute Name | Code | Value Type|MUST| MAY | NOT| NOT|Encr|
|------------------|------|------------|----+-----+----+-----|----| |------------------|------|------------|----+-----+----+-----|----|
| NAS-Port | 5 | Unsigned32 | M | P | | V | Y | | NAS-Port | 5 | Unsigned32 | M | P | | V | Y |
| NAS-Port-Id | 87 | UTF8String | M | P | | V | Y | | NAS-Port-Id | 87 | UTF8String | M | P | | V | Y |
| Calling-Station- | 31 | UTF8String | M | P | | V | Y | | Calling-Station- | 31 | UTF8String | M | P | | V | Y |
| Id | | | | | | | | | Id | | | | | | | |
| Framed-IP-Address| 8 | OctetString| M | P | | V | Y | | Framed-IP-Address| 8 | OctetString| M | P | | V | Y |
| Framed-Interface-| 96 | Unsigned64 | M | P | | V | Y | | Framed-Interface-| 96 | Unsigned64 | M | P | | V | Y |
| Id | | | | | | | | | Id | | | | | | | |
| Framed-IPv6- | 97 | OctetString| M | P | | V | Y | | Framed-IPv6- | 97 | OctetString| M | P | | V | Y |
| Prefix | | | | | | | | | Prefix | | | | | | | |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
Table 2: Reused NASREQ Diameter application AVPs. Please refer to Table 2: Reused NASREQ Diameter application AVPs. Please refer to
[RFC3588] for the definition of the Diameter AVP flag rules and the [RFC6733] for the definition of the Diameter AVP Flag rules and the
associated abbreviations used in the table. associated abbreviations used in the table.
8.4. Reused AVPs from RFC 4675 8.4. Reused AVPs from RFC 4675
The following table describes the AVPs reused from "RADIUS Attributes The following table describes the AVPs reused from "RADIUS Attributes
for Virtual LAN and Priority Support" specification [RFC4675]; their for Virtual LAN and Priority Support" [RFC4675]; their AVP Code
AVP Code values, types, and possible flag values; and whether the AVP values, types, and possible flag values; and whether the AVP MAY be
MAY be encrypted. The [RFC3588] specifies the AVP Flag rules for encrypted. [RFC6733] specifies the AVP Flag rules for AVPs in
AVPs in section 4.5. The Diameter AVP rules are defined in the Section 4.5. The Diameter AVP rules are defined in [RFC6733],
Section 4.
[RFC3588], section 4.
+---------------------+ +---------------------+
| AVP Flag rules | | AVP Flag Rules |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
| | AVP | | | |SHLD| MUST| | | | AVP | | | |SHLD| MUST| |
| Attribute Name | Code | Value Type|MUST| MAY | NOT| NOT|Encr| | Attribute Name | Code | Value Type|MUST| MAY | NOT| NOT|Encr|
|------------------|------|------------|----+-----+----+-----|----| |------------------|------|------------|----+-----+----+-----|----|
| Egress-VLANID | 56 | OctetString| M | P | | V | Y | | Egress-VLANID | 56 | OctetString| M | P | | V | Y |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
Table 3: Reused attributes from RFC 4675. Please refer to [RFC3588] Table 3: Reused attributes from [RFC4675]. Please refer to [RFC6733]
for the definition of the Diameter AVP flag rules and the associated for the definition of the Diameter AVP Flag rules and the associated
abbreviations used in the table. abbreviations used in the table.
8.5. Reused AVPs from Diameter QoS Application 8.5. Reused AVPs from Diameter QoS Application
The following table describes the AVPs reused from the Traffic The following table describes the AVPs reused from the "Traffic
Classification and Quality of Service (QoS) Attributes for Diameter Classification and Quality of Service (QoS) Attributes for Diameter"
[RFC5777]; their AVP Code values, types, and possible flag values; [RFC5777]; their AVP Code values, types, and possible flag values;
and whether the AVP MAY be encrypted. The [RFC3588] specifies the and whether the AVP MAY be encrypted. [RFC6733] specifies the AVP
AVP Flag rules for AVPs in section 4.5. The Diameter AVP rules are Flag rules for AVPs in Section 4.5. The Diameter AVP rules are
defined in the [RFC3588], section 4. defined in [RFC6733], Section 4.
+---------+ +---------+
| AVP | | AVP |
| Flag | | Flag |
| rules | | Rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP | | | | | AVP | | | |
| Attribute Name Code Data Type |MUST |MAY| Encr | | Attribute Name Code Data Type |MUST |MAY| Encr |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|Port 530 Integer32 | M | P | Y | |Port 530 Integer32 | M | P | Y |
|Protocol 513 Enumerated | M | P | Y | |Protocol 513 Enumerated | M | P | Y |
|Direction 514 Enumerated | M | P | Y | |Direction 514 Enumerated | M | P | Y |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
Table 4: Reused QoS-attributes. Please refer to [RFC3588] for the Table 4: Reused QoS-attributes. Please refer to [RFC6733] for the
definition of the Diameter AVP flag rules and the associated definition of the Diameter AVP Flag rules and the associated
abbreviations used in the table. abbreviations used in the table.
8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter Application 8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter Application
The following table describes the AVPs reused from the Diameter e4 The following table describes the AVPs reused from the Diameter e4
Application [ETSIES283034]; their AVP Code values, types, and Application [ETSIES283034]; their AVP Code values, types, and
possible flag values; and whether the AVP MAY be encrypted. The possible flag values; and whether the AVP MAY be encrypted.
[RFC3588] specifies the AVP Flag rules for AVPs in section 4.5. The [RFC6733] specifies the AVP Flag rules for AVPs in Section 4.5. The
Diameter AVP rules are defined in the [RFC3588], section 4. The Diameter AVP rules are defined in [RFC6733], Section 4. The
Vendor-ID field in these AVP header will be set to ETSI (13019). Vendor-ID field in these AVP header will be set to ETSI (13019).
+---------+ +---------+
| AVP | | AVP |
| Flag | | Flag |
| rules | | Rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP | | | | | AVP | | | |
| Attribute Name Code Data Type |MUST |MAY| Encr | | Attribute Name Code Data Type |MUST |MAY| Encr |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|Address-Realm 301 OctetString | M,V | | Y | |Address-Realm 301 OctetString | M,V | | Y |
|Logical-Access-Id 302 OctetString | V | M | Y | |Logical-Access-Id 302 OctetString | V | M | Y |
|Physical-Access-ID 313 UTF8String | V | M | Y | |Physical-Access-ID 313 UTF8String | V | M | Y |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
Table 5: Reused AVPs from Diameter e4 application. Please refer to Table 5: Reused AVPs from the Diameter e4 application. Please refer
[RFC3588] for the definition of the Diameter AVP flag rules and the to [RFC6733] for the definition of the Diameter AVP Flag rules and
associated abbreviations used in the table. the associated abbreviations used in the table.
8.7. DNCA Defined AVPs 8.7. DNCA-Defined AVPs
The following table describes the new Diameter AVPs defined in this The following table describes the new Diameter AVPs defined in this
document; their AVP Code values, types, and possible flag values; and document; their AVP Code values, types, and possible flag values; and
whether the AVP MAY be encrypted. The [RFC3588] specifies the AVP whether the AVP MAY be encrypted. [RFC6733] specifies the AVP Flag
Flag rules for AVPs in section 4.5. The Diameter AVP rules are rules for AVPs in Section 4.5. The Diameter AVP rules are defined in
defined in the [RFC3588], section 4. The AVPs defined here MUST NOT [RFC6733], Section 4. The AVPs defined here MUST NOT have the 'V'
have the V bit in the AVP Flag set. bit in the AVP Flags field set.
+---------+ +---------+
| AVP | | AVP |
| Flag | | Flag |
| rules | | Rules |
+--------------------------------------------------|-----+---+------+ +--------------------------------------------------|-----+---+------+
| AVP | | | | | AVP | | | |
| Attribute Name Code Data Type |MUST |MAY| Encr | | Attribute Name Code Sect. Data Type |MUST |MAY| Encr |
+--------------------------------------------------+-----+---+------+ +--------------------------------------------------+-----+---+------+
|NC-Request-Type TBD.AX 8.7.1 Enumerated | M | P | Y | |NC-Request-Type 595 8.7.1 Enumerated | M | P | Y |
|NAT-Control-Install TBD.AX 8.7.2 Grouped | M | P | Y | |NAT-Control-Install 596 8.7.2 Grouped | M | P | Y |
|NAT-Control-Remove TBD.AX 8.7.3 Grouped | M | P | Y | |NAT-Control-Remove 597 8.7.3 Grouped | M | P | Y |
|NAT-Control-Definition TBD.AX 8.7.4 Grouped | M | P | Y | |NAT-Control-Definition 598 8.7.4 Grouped | M | P | Y |
|NAT-Internal-Address TBD.AX 8.7.5 Grouped | M | P | Y | |NAT-Internal-Address 599 8.7.5 Grouped | M | P | Y |
|NAT-External-Address TBD.AX 8.7.6 Grouped | M | P | Y | |NAT-External-Address 600 8.7.6 Grouped | M | P | Y |
|Max-NAT-Bindings TBD.AX 8.7.7 Unsigned32 | M | P | Y | |Max-NAT-Bindings 601 8.7.7 Unsigned32 | M | P | Y |
|NAT-Control- TBD.AX 8.7.8 OctetString| M | P | Y | |NAT-Control- 602 8.7.8 OctetString| M | P | Y |
| Binding-Template | | | | | Binding-Template | | | |
|Duplicate- TBD.AX 8.7.9 UTF8String | M | P | Y | |Duplicate- 603 8.7.9 UTF8String | M | P | Y |
| Session-ID | | | | | Session-Id | | | |
|NAT-External-Port- TBD.AX 8.7.10 Enumerated | M | P | Y | |NAT-External-Port- 604 8.7.10 Enumerated | M | P | Y |
| Style | | | | | Style | | | |
|NAT-Control-Record TBD.AX 9.2.1 Grouped | M | P | Y | |NAT-Control-Record 605 9.2.1 Grouped | M | P | Y |
|NAT-Control- TBD.AX 9.2.2 Enumerated | M | P | Y | |NAT-Control- 606 9.2.2 Enumerated | M | P | Y |
| Binding-Status | | | | | Binding-Status | | | |
|Current-NAT-Bindings TBD.AX 9.2.3 Unsigned32 | M | P | Y | |Current-NAT-Bindings 607 9.2.3 Unsigned32 | M | P | Y |
+--------------------------------------------------+-----+---+------+ +--------------------------------------------------+-----+---+------+
Table 6: New Diameter AVPs. Please refer to [RFC3588] for the Table 6: New Diameter AVPs. Please refer to [RFC6733] for the
definition of the Diameter AVP flag rules and the associated definition of the Diameter AVP Flag rules and the associated
abbreviations used in the table. abbreviations used in the table.
8.7.1. NC-Request-Type AVP 8.7.1. NC-Request-Type AVP
The NC-Request-Type AVP (AVP Code TBD.AX) is of type Enumerated and The NC-Request-Type AVP (AVP Code 595) is of type Enumerated and
contains the reason for sending the NAT-Control-Request command. It contains the reason for sending the NAT-Control-Request command. It
shall be present in all NAT-Control-Request messages. shall be present in all NAT-Control-Request messages.
The following values are defined: The following values are defined:
INITIAL_REQUEST (1) INITIAL_REQUEST (1)
An Initial Request is to initiate a Diameter NAT control An Initial Request is to initiate a Diameter NAT control
session between the DNCA Diameter peers. session between the DNCA Diameter peers.
UPDATE_REQUEST (2) UPDATE_REQUEST (2)
An Update Request is used to update bindings previously An Update Request is used to update bindings previously
installed on a given access session, to add new binding on a installed on a given access session, to add new binding on a
given access session, or to remove one or several binding(s) given access session, or to remove one or several binding(s)
activated on a given access session. activated on a given access session.
QUERY_REQUEST (3) QUERY_REQUEST (3)
Query Request is used to query a NAT-device about the currently Query Request is used to query a NAT device about the currently
installed bindings for an endpoint classifier. installed bindings for an endpoint classifier.
8.7.2. NAT-Control-Install AVP 8.7.2. NAT-Control-Install AVP
The NAT-Control AVP (AVP code TBD.AX) is of type Grouped, and it is The NAT-Control-Install AVP (AVP code 596) is of type Grouped, and it
used to activate or install NAT bindings. It also contains Max-NAT- is used to activate or install NAT-bindings. It also contains Max-
Bindings that defines the maximum number of NAT bindings allowed for NAT-Bindings that defines the maximum number of NAT-bindings allowed
an endpoint and the NAT-Control-Binding-Template that references a for an endpoint and the NAT-Control-Binding-Template that references
predefined template on the NAT-device that may contain static a predefined template on the NAT device that may contain static
binding, a maximum number of bindings allowed, an IP-address pool binding, a maximum number of bindings allowed, an IP address pool
from which external binding addresses should be allocated, etc. If from which external binding addresses should be allocated, etc. If
the NAT-External-Port-Style AVP is present, then the NAT-device MUST the NAT-External-Port-Style AVP is present, then the NAT device MUST
select the external ports for the NAT-Bindings as per the style select the external ports for the NAT-bindings, per the style
specified. The NAT-External-Port-Style is applicable for NAT- specified. The NAT-External-Port-Style is applicable for NAT-
Bindings defined by the NAT-Control-Definition AVPs whose NAT- bindings defined by the NAT-Control-Definition AVPs whose NAT-
External-Address or Port AVPs within the NAT-External-Address are External-Address or Port AVPs within the NAT-External-Address are
unspecified. unspecified.
AVP format: AVP format:
NAT-Control-Install ::= < AVP Header: TBD.AX > NAT-Control-Install ::= < AVP Header: 596 >
* [ NAT-Control-Definition ] * [ NAT-Control-Definition ]
[ NAT-Control-Binding-Template ] [ NAT-Control-Binding-Template ]
[ Max-NAT-Bindings ] [ Max-NAT-Bindings ]
[ NAT-External-Port-Style ] [ NAT-External-Port-Style ]
* [ AVP ] * [ AVP ]
8.7.3. NAT-Control-Remove AVP 8.7.3. NAT-Control-Remove AVP
The NAT-Control-Remove AVP (AVP code TBD.AX) is of type Grouped, and The NAT-Control-Remove AVP (AVP code 597) is of type Grouped, and it
it is used to deactivate or remove NAT-bindings. At least one of the is used to deactivate or remove NAT-bindings. At least one of the
two AVPs (NAT-Control-Definition AVP, NAT-Control-Binding-Template two AVPs (NAT-Control-Definition AVP or NAT-Control-Binding-Template
AVP) SHOULD be present in the NAT-Control-Remove AVP. AVP) SHOULD be present in the NAT-Control-Remove AVP.
AVP format: AVP format:
NAT-Control-Remove ::= < AVP Header: TBD.AX > NAT-Control-Remove ::= < AVP Header: 597 >
* [ NAT-Control-Definition ] * [ NAT-Control-Definition ]
[ NAT-Control-Binding-Template ] [ NAT-Control-Binding-Template ]
* [ AVP ] * [ AVP ]
8.7.4. NAT-Control-Definition AVP 8.7.4. NAT-Control-Definition AVP
The NAT-Control-Definition AVP (AVP code TBD.AX) is of type Grouped, The NAT-Control-Definition AVP (AVP code 598) is of type Grouped, and
and it describes a binding. it describes a binding.
The NAT-Control-Definition AVP uniquely identifies the binding The NAT-Control-Definition AVP uniquely identifies the binding
between the DNCA Diameter peers. between the DNCA Diameter peers.
If both the NAT-Internal-Address and NAT-External-Address AVP(s) are If both the NAT-Internal-Address and NAT-External-Address AVP(s) are
supplied, it is a pre-defined binding. supplied, it is a predefined binding.
If the NAT-External-Address AVP is not specified then the NAT-device If the NAT-External-Address AVP is not specified, then the NAT device
MUST select the external port as per the NAT-External-Port-Style AVP, MUST select the external port as per the NAT-External-Port-Style AVP,
if present in the NAT-Control-Definition AVP. if present in the NAT-Control-Definition AVP.
The Protocol AVP describes the transport protocol for the binding. The Protocol AVP describes the transport protocol for the binding.
The NAT-Control-Definition AVP can contain either zero or one The NAT-Control-Definition AVP can contain either zero or one
Protocol AVP. If the Protocol AVP is omitted and if both internal Protocol AVP. If the Protocol AVP is omitted and if both internal
and external IP-address are specified then the binding reserves the and external IP addresses are specified, then the binding reserves
IP-addresses for all transport protocols. the IP addresses for all transport protocols.
The Direction AVP is of type Enumerated. It specifies the direction The Direction AVP is of type Enumerated. It specifies the direction
for the binding. The values of the enumeration applicable in this for the binding. The values of the enumeration applicable in this
context are: "IN","OUT". If Direction AVP is OUT or absent, the NAT- context are: "IN","OUT". If Direction AVP is OUT or absent, the NAT-
Internal-Address refers to the IP-address of the endpoint that needs Internal-Address refers to the IP address of the endpoint that needs
to be translated. If Direction AVP is "IN", NAT-Internal-Address is to be translated. If Direction AVP is "IN", NAT-Internal-Address is
the destination IP-address that has to be translated. the destination IP address that has to be translated.
AVP format: AVP format:
NAT-Control-Definition ::= < AVP Header: TBD.AX > NAT-Control-Definition ::= < AVP Header: 598 >
{ NAT-Internal-Address } { NAT-Internal-Address }
[ Protocol ] [ Protocol ]
[ Direction ] [ Direction ]
[ NAT-External-Address ] [ NAT-External-Address ]
[ Session-Id ] [ Session-Id ]
* [ AVP ] * [ AVP ]
8.7.5. NAT-Internal-Address AVP 8.7.5. NAT-Internal-Address AVP
The NAT-Internal-Address AVP (AVP code TBD.AX) is of type Grouped. The NAT-Internal-Address AVP (AVP code 599) is of type Grouped. It
It describes the internal IP-address and port for a binding. Framed- describes the internal IP address and port for a binding. Framed-
IPV6-Prefix and Framed-IP-Address AVPs are mutually exclusive. The IPV6-Prefix and Framed-IP-Address AVPs are mutually exclusive. The
endpoint identifier Framed-IP-Address, Framed-IPv6-Prefix and the endpoint identifier Framed-IP-Address, Framed-IPv6-Prefix, and the
internal address in this NAT-Internal-Address AVP to install NAT- internal address in this NAT-Internal-Address AVP to install NAT-
bindings for the session MUST match. bindings for the session MUST match.
AVP format: AVP format:
NAT-Internal-Address ::= < AVP Header: 599 >
NAT-Internal-Address ::= < AVP Header: TBD.AX >
[ Framed-IP-Address ] [ Framed-IP-Address ]
[ Framed-IPv6-Prefix ] [ Framed-IPv6-Prefix ]
[ Port] [ Port]
* [ AVP ] * [ AVP ]
8.7.6. NAT-External-Address AVP 8.7.6. NAT-External-Address AVP
The NAT-External-Address AVP (AVP code TBD.AX) is of type Grouped, The NAT-External-Address AVP (AVP code 600) is of type Grouped, and
and it describes the external IP-address and port for a binding. The it describes the external IP address and port for a binding. The
external IP-address specified in this attribute can be reused for external IP address specified in this attribute can be reused for
multiple endpoints by specifying the same address in the respective multiple endpoints by specifying the same address in the respective
NAT-External-Address AVPs. If the external IP-address is not NAT-External-Address AVPs. If the external IP address is not
specified and the NAT-External-Port-Style AVP is specified in the specified and the NAT-External-Port-Style AVP is specified in the
NAT-Control-Definition AVP then the NAT-device MUST select external NAT-Control-Definition AVP, then the NAT device MUST select an
port as per the NAT-External-Port-Style AVP. external port as per the NAT-External-Port-Style AVP.
AVP format: AVP format:
NAT-External-Address ::= < AVP Header: TBD.AX > NAT-External-Address ::= < AVP Header: 600 >
[ Framed-IP-Address ] [ Framed-IP-Address ]
[ Port ] [ Port ]
* [ AVP ] * [ AVP ]
8.7.7. Max-NAT-Bindings 8.7.7. Max-NAT-Bindings
The Max-NAT-Bindings AVP (AVP code TBD.AX) is of type Unsigned32. It The Max-NAT-Bindings AVP (AVP code 601) is of type Unsigned32. It
indicates the maximum number of NAT-bindings allowed for a particular indicates the maximum number of NAT-bindings allowed for a particular
endpoint. endpoint.
8.7.8. NAT-Control-Binding-Template AVP 8.7.8. NAT-Control-Binding-Template AVP
The NAT-Control-Binding-Template AVP (AVP code TBD.AX) is of type The NAT-Control-Binding-Template AVP (AVP code 602) is of type
OctetString. It defines a name for a policy template that is OctetString. It defines a name for a policy template that is
predefined at the NAT-device. Details on the contents and structure predefined at the NAT device. Details on the contents and structure
of the template and configuration are outside the scope of this of the template and configuration are outside the scope of this
document. The policy to which this AVP refers to may contain NAT- document. The policy to which this AVP refers may contain NAT-
bindings, IP-address pool for allocating the external IP-address of a bindings, an IP address pool for allocating the external IP address
NAT-binding, and maximum number of allowed NAT-bindings. Such policy of a NAT-binding, and a maximum number of allowed NAT-bindings. Such
template can be reused by specifying the same NAT-Control-Binding- a policy template can be reused by specifying the same NAT-Control-
Template AVP in the corresponding NAT-Control-Install AVPs of Binding-Template AVP in the corresponding NAT-Control-Install AVPs of
multiple endpoints. multiple endpoints.
8.7.9. Duplicate-Session-Id AVP 8.7.9. Duplicate-Session-Id AVP
The Duplicate-Session-Id AVP (AVP Code TBD.AX) is of type UTF8String. The Duplicate-Session-Id AVP (AVP Code 603) is of type UTF8String.
It is used to report errors and contains the Session-Id of an It is used to report errors and contains the Session-Id of an
existing session. existing session.
8.7.10. NAT-External-Port-Style AVP 8.7.10. NAT-External-Port-Style AVP
The NAT-External-Port-Style AVP (AVP Code TBD.AX) is of type The NAT-External-Port-Style AVP (AVP Code 604) is of type Enumerated
Enumerated and contains the style to be followed while selecting the and contains the style to be followed while selecting the external
external port for a NAT-Binding relative to the internal port. port for a NAT-binding relative to the internal port.
The following values are defined: The following values are defined:
FOLLOW_INTERNAL_PORT_STYLE (1) FOLLOW_INTERNAL_PORT_STYLE (1)
External port numbers selected MUST follow the same sequence External port numbers selected MUST follow the same sequence
and oddity as the internal ports of the NAT-bindings. The port and oddity as the internal ports of the NAT-bindings. The port
odditity is required to support protocols like RTP and RTCP as oddity is required to support protocols like RTP and RTCP as
defined in [RFC3550]. If for example the internal port in a defined in [RFC3550]. If for example the internal port in a
requested NAT-binding is odd numbered then the external port requested NAT-binding is odd numbered, then the external port
allocated MUST also be odd numbered, and vice versa for an even allocated MUST also be odd numbered, and vice versa for an even
numbered port. In addition, the sequence of port numbering is numbered port. In addition, the sequence of port numbering is
maintained: If internal ports are consecutive, then the NAT- maintained: if internal ports are consecutive, then the NAT
device MUST choose consecutive external ports for the NAT- device MUST choose consecutive external ports for the NAT-
bindings. bindings.
9. Accounting Commands 9. Accounting Commands
The DNCA reuses session based accounting as defined in the Diameter The DNCA reuses session-based accounting as defined in the Diameter
Base Protocol[RFC3588] to report the bindings per endpoint. This base protocol [RFC6733] to report the bindings per endpoint. This
reporting is achieved by sending Diameter Accounting Requests (ACR) reporting is achieved by sending Diameter Accounting-Request (ACR)
[Start, Interim and Stop] from the DNCA Diameter peer within the NAT- commands [Start, Interim, and Stop] from the DNCA Diameter peer
device to its associated DNCA Diameter peer within the NAT- within the NAT device to its associated DNCA Diameter peer within the
controller. NAT controller.
The DNCA Diameter peer within the NAT-device sends an ACR Start on The DNCA Diameter peer within the NAT device sends an ACR Start on
receiving a NCR with NC-Request-Type AVP set to INITIAL_REQUEST for a receiving an NCR with NC-Request-Type AVP set to INITIAL_REQUEST for
session or on creation of the first binding for a session requested a session or on creation of the first binding for a session requested
in an earlier NCR. DNCA may send ACR Interim updates, if required, in an earlier NCR. DNCA may send ACR Interim updates, if required,
either due to a change in bindings resulting from a NCR with NC- either due to a change in bindings resulting from an NCR with NC-
Request-Type AVP set to UPDATE_REQUEST, or periodically as specified Request-Type AVP set to UPDATE_REQUEST, periodically as specified in
in Acct-Interim-Interval by the DNCA Diameter peer within the NAT- Acct-Interim-Interval by the DNCA Diameter peer within the NAT
controller, or when it creates or tears down bindings. An ACR Stop controller, or when it creates or tears down bindings. An ACR Stop
is sent by the DNCA Diameter peer within the NAT-device on receiving is sent by the DNCA Diameter peer within the NAT device on receiving
STR. an STR message.
The function of correlating the multiple bindings used by an endpoint The function of correlating the multiple bindings used by an endpoint
at any given time is relegated to the post processor. at any given time is relegated to the post processor.
The DNCA Diameter peer within the NAT-device may trigger an interim The DNCA Diameter peer within the NAT device may trigger an Interim
accounting record when the maximum number of bindings, if received in accounting record when the maximum number of bindings, if received in
an NCR, is reached. an NCR, is reached.
9.1. NAT Control Accounting Messages 9.1. NAT Control Accounting Messages
The ACR and ACA messages are reused as defined in the Diameter Base The ACR and ACA messages are reused as defined in the Diameter base
Protocol [RFC3588] for exchanging endpoint NAT binding details protocol [RFC6733] for exchanging endpoint NAT-binding details
between the DNCA Diameter peers. The DNCA Application IDs is used in between the DNCA Diameter peers. The DNCA Application ID is used in
the accounting commands. ACR contains one or more optional NAT- the accounting commands. The ACR contains one or more optional NAT-
Control-Record AVPs to report the bindings. The NAT-device indicates Control-Record AVPs to report the bindings. The NAT device indicates
the number of allocated NAT bindings to the NAT-controller using the the number of allocated NAT-bindings to the NAT controller using the
Current-NAT-Bindings AVP. This number needs to match the number of Current-NAT-Bindings AVP. This number needs to match the number of
bindings identified as active within the NAT-Control-Record AVP. bindings identified as active within the NAT-Control-Record AVP.
9.2. NAT Control Accounting AVPs 9.2. NAT Control Accounting AVPs
In addition to AVPs for ACR specified in [RFC3588], the DNCA Diameter In addition to AVPs for ACR specified in [RFC6733], the DNCA Diameter
peer within the NAT-device must add the NAT-Control-Record AVP. peer within the NAT device must add the NAT-Control-Record AVP.
9.2.1. NAT-Control-Record 9.2.1. NAT-Control-Record
The NAT-Control-Record AVP (AVP code TBD.AX) is of type Grouped. It The NAT-Control-Record AVP (AVP code 605) is of type Grouped. It
describes a binding and its status. If NAT-Control-Binding-Status is describes a binding and its status. If NAT-Control-Binding-Status is
set to Created, Event-Timestamp indicates the binding creation time. set to Created, Event-Timestamp indicates the binding creation time.
If NAT-Control-Binding-Status is set to Removed, Event-Timestamp If NAT-Control-Binding-Status is set to Removed, Event-Timestamp
indicates the binding removal time. If NAT-Control-Binding-Status is indicates the binding removal time. If NAT-Control-Binding-Status is
active, Event-Timestamp need not be present; if a value is present, active, Event-Timestamp need not be present; if a value is present,
it indicates that binding is active at the given time. it indicates that binding is active at the given time.
NAT-Control-Record ::= < AVP Header: TBD.AX > NAT-Control-Record ::= < AVP Header: 605 >
{ NAT-Control-Definition } { NAT-Control-Definition }
{ NAT-Control-Binding-Status } { NAT-Control-Binding-Status }
[ Event-Timestamp ] [ Event-Timestamp ]
9.2.2. NAT-Control-Binding-Status 9.2.2. NAT-Control-Binding-Status
The NAT-Control-Binding-Status AVP (AVP code TBD.AX) is of type The NAT-Control-Binding-Status AVP (AVP code 606) is of type
enumerated. It indicates the status of the binding - created, enumerated. It indicates the status of the binding: created,
removed, or active. removed, or active.
The following values are defined: The following values are defined:
Created (1) Created (1)
NAT binding is created. NAT-binding is created.
Active (2) Active (2)
NAT binding is active. NAT-binding is active.
Removed (3) Removed (3)
NAT binding was removed. NAT-binding was removed.
9.2.3. Current-NAT-Bindings 9.2.3. Current-NAT-Bindings
The Current-NAT-Bindings AVP (AVP code TBD.AX) is of type Unsigned32. The Current-NAT-Bindings AVP (AVP code 607) is of type Unsigned32.
It indicates the number of NAT bindings active on the NAT-device. It indicates the number of NAT-bindings active on the NAT device.
10. AVP Occurrence Table 10. AVP Occurrence Tables
The following sections present the AVPs defined in this document and The following sections present the AVPs defined in this document and
specify the Diameter messages in which they can be present. Note: specify the Diameter messages in which they can be present. Note:
AVPs that can only be present within a Grouped AVP are not AVPs that can only be present within a Grouped AVP are not
represented in this table. represented in this table.
The table uses the following symbols: The table uses the following symbols:
0 The AVP MUST NOT be present in the message. 0 The AVP MUST NOT be present in the message.
skipping to change at page 42, line 39 skipping to change at page 42, line 23
message. It is considered an error if there is more message. It is considered an error if there is more
than one instance of the AVP. than one instance of the AVP.
1 One instance of the AVP MUST be present in the message. 1 One instance of the AVP MUST be present in the message.
1+ At least one instance of the AVP MUST be present in the 1+ At least one instance of the AVP MUST be present in the
message. message.
10.1. DNCA AVP Table for NAT Control Initial and Update Requests 10.1. DNCA AVP Table for NAT Control Initial and Update Requests
The following table lists DNCA specific AVPs that have to be present The following table lists DNCA-specific AVPs that have to be present
in NCRs and NCAs with NC-Request-Type set to INITIAL_REQUEST or in NCRs and NCAs with the NC-Request-Type set to INITIAL_REQUEST or
UPDATE_REQUEST. UPDATE_REQUEST.
+-------------------+ +-------------------+
| Command Code | | Command Code |
+-----------------------------------+-------------------+ +-----------------------------------+-------------------+
| Attribute Name NCR NCA | | Attribute Name NCR NCA |
+-------------------------------------------------------+ +-------------------------------------------------------+
|NC-Request-Type 1 1 | |NC-Request-Type 1 1 |
|NAT-Control-Install 0-1 0 | |NAT-Control-Install 0-1 0 |
|NAT-Control-Remove 0-1 0 | |NAT-Control-Remove 0-1 0 |
|NAT-Control-Definition 0 0 | |NAT-Control-Definition 0 0 |
|Current-NAT-Bindings 0 0 | |Current-NAT-Bindings 0 0 |
|Duplicate-Session-Id 0 0-1 | |Duplicate-Session-Id 0 0-1 |
+-------------------------------------------------------+ +-------------------------------------------------------+
Note that any combination of "NAT-Control-Install" and "NAT-Control- Note that any combination of NAT-Control-Install and NAT-Control-
Remove" AVPs could be present in an update or initial requests. Remove AVPs could be present in an update or initial requests.
Consider the following examples: Consider the following examples:
Neither "NAT-Control-Install AVP" nor "NAT-Control-Remove AVP" are Neither the NAT-Control-Install AVP nor the NAT-Control-Remove AVP
present: This could for example be the case if the NAT-controller is present: This could, for example, be the case if the NAT
would only want to receive accounting information, but not control controller would only want to receive accounting information but
NAT-bindings. not control NAT-bindings.
Only "NAT-Control-Install AVP" is present: This could for example Only NAT-Control-Install AVP is present: This could, for example,
be the case if a new NAT-binding is installed for an existing be the case if a new NAT-binding is installed for an existing
session. session.
Only "NAT-Control-Remove AVP" is present: This could for example Only NAT-Control-Remove AVP is present: This could, for example,
be the case if a new NAT-binding is removed from an existing be the case if a new NAT-binding is removed from an existing
session. session.
Both, "NAT-Control-Install AVP" and "NAT-Control-Remove AVP" are Both, NAT-Control-Install AVP and NAT-Control-Remove AVP are
present: This could for example be the case if a formerly created present: This could, for example. be the case if a formerly
NAT-binding is removed and a new NAT-binding is established within created NAT-binding is removed and a new NAT-binding is
the same request. established within the same request.
10.2. DNCA AVP Table for Session Query request 10.2. DNCA AVP Table for Session Query Requests
The following table lists DNCA specific AVPs that have to be present The following table lists DNCA-specific AVPs that have to be present
in NCRs and NCAs with NC-Request-Type set to QUERY_REQUEST. in NCRs and NCAs with the NC-Request-Type set to QUERY_REQUEST.
+-------------------+ +-------------------+
| Command Code | | Command Code |
+-----------------------------------+-------------------+ +-----------------------------------+-------------------+
| Attribute Name NCR NCA | | Attribute Name NCR NCA |
+-------------------------------------------------------+ +-------------------------------------------------------+
|NC-Request-Type 1 1 | |NC-Request-Type 1 1 |
|NAT-Control-Install 0 0 | |NAT-Control-Install 0 0 |
|NAT-Control-Remove 0 0 | |NAT-Control-Remove 0 0 |
|NAT-Control-Definition 0 0+ | |NAT-Control-Definition 0 0+ |
|NAT-External-Address 0+ 0 | |NAT-External-Address 0+ 0 |
|Current-NAT-Bindings 0 1 | |Current-NAT-Bindings 0 1 |
|Duplicate-Session-Id 0 0 | |Duplicate-Session-Id 0 0 |
+-------------------------------------------------------+ +-------------------------------------------------------+
10.3. DNCA AVP Table for Accounting Message 10.3. DNCA AVP Table for Accounting Messages
The following table lists DNCA specific AVPs, which may or may not be The following table lists DNCA-specific AVPs, which may or may not be
present in ACR and ACA messages. present in ACR and ACA messages.
+-------------------+ +-------------------+
| Command Code | | Command Code |
+-----------------------------------+-------------------+ +-----------------------------------+-------------------+
| Attribute Name ACR ACA | | Attribute Name ACR ACA |
+-------------------------------------------------------+ +-------------------------------------------------------+
|NAT-Control-Record 0+ 0 | |NAT-Control-Record 0+ 0 |
|Current-NAT-Bindings 1 0 | |Current-NAT-Bindings 1 0 |
+-------------------------------------------------------+ +-------------------------------------------------------+
11. IANA Considerations 11. IANA Considerations
This section contains the namespaces that have either been created in This section contains either the namespaces that have been created in
this specification, or the values assigned to existing namespaces this specification or the values assigned to existing namespaces
managed by IANA. managed by IANA.
In the subsections below, when we speak about review by a Designated In the subsections below, when we speak about review by a Designated
Expert, please note that the designated expert will be assigned by Expert [RFC5226], please note that the Designated Expert will be
the IESG. Initially, such Expert discussions take place on the AAA assigned by the IESG. Initially, such Expert discussions take place
WG mailing list. on the AAA WG mailing list.
11.1. Application Identifier 11.1. Application Identifier
This specification assigns the value <TBD.APP-ID>, 'Diameter NAT This specification assigns the value 12, 'Diameter NAT Control
Control Application', to the Application Identifier namespace defined Application', to the Application Identifier namespace defined in
in [RFC3588]. See Section 4 for more information. [RFC6733]. See Section 4 for more information.
11.2. Command Codes 11.2. Command Codes
This specification uses the value <TBD.COM-CODE> from the Command This specification uses the value 330 from the Command code namespace
code namespace defined in [RFC3588] for the NAT-Control-Request defined in [RFC6733] for the NAT-Control-Request (NCR) and NAT-
(NCR), NAT-Control-Answer (NCA) commands. See Section 6.1 and Control-Answer (NCA) commands. See Section 6.1 and Section 6.2 for
Section 6.2 for more information on these commands. more information on these commands.
11.3. AVP Codes 11.3. AVP Codes
This specification assigns the values <TBD.AX> from the AVP code This specification assigns the values 595-607 from the AVP Code
namespace defined in [RFC3588]. See Section 8.7 for the assignment namespace defined in [RFC6733]. See Section 8.7 for the assignment
of the namespace in this specification. of the namespace in this specification.
11.4. Result-Code AVP Values 11.4. Result-Code AVP Values
This specification assigns the values <TBD.RCX> (4xxx, 5xxx, 5xxx, This specification assigns the values 4014 and 5042-5047 from the
5xxx, 5xxx,5xxx) from the Result-Code AVP value namespace defined in Result-Code AVP value namespace defined in [RFC6733]. See
[RFC3588]. See Section 8.2 for the assignment of the namespace in Section 8.2 for the assignment of the namespace in this
this specification. specification.
11.5. NC-Request-Type AVP 11.5. NC-Request-Type AVP
As defined in Section 8.7.1, the NC-Request-Type AVP includes As defined in Section 8.7.1, the NC-Request-Type AVP includes
Enumerated type values 1 - 3. IANA has created and is maintaining a Enumerated type values 1-3. IANA has created and is maintaining a
namespace for this AVP. All remaining values are available for namespace for this AVP. All remaining values are available for
assignment by a Designated Expert [RFC5226]. assignment by a Designated Expert [RFC5226].
11.6. NAT-External-Port-Style AVP 11.6. NAT-External-Port-Style AVP
As defined in Section 8.7.10, the NAT-External-Port-Style AVP As defined in Section 8.7.10, the NAT-External-Port-Style AVP
includes Enumerated type value 1. IANA has created and is includes Enumerated type value 1. IANA has created and is
maintaining a namespace for this AVP. All remaining values are maintaining a namespace for this AVP. All remaining values are
available for assignment by a Designated Expert [RFC5226]. available for assignment by a Designated Expert [RFC5226].
11.7. NAT-Control-Binding-Status AVP 11.7. NAT-Control-Binding-Status AVP
As defined in Section 8.7.1, the NAT-Control-Binding-Status AVP As defined in Section 8.7.1, the NAT-Control-Binding-Status AVP
includes Enumerated type values 1 - 3. IANA has created and is includes Enumerated type values 1-3. IANA has created and is
maintaining a namespace for this AVP. All remaining values are maintaining a namespace for this AVP. All remaining values are
available for assignment by a Designated Expert [RFC5226]. available for assignment by a Designated Expert [RFC5226].
12. Security Considerations 12. Security Considerations
This document describes procedures for controlling NAT related This document describes procedures for controlling NAT-related
attributes and parameters by an entity, which is non-local to the attributes and parameters by an entity, which is non-local to the
device performing NAT. This section discusses security device performing NAT. This section discusses security
considerations for DNCA. This includes the interactions between the considerations for DNCA. This includes the interactions between the
Diameter peers within a NAT-controller and a NAT-device as well as Diameter peers within a NAT controller and a NAT device as well as
general considerations for NAT-control in a service provider network. general considerations for a NAT-control in a service provider
network.
Security between a NAT-controller and a NAT-device has a number of Security between a NAT controller and a NAT device has a number of
components: authentication, authorization, integrity, and components: authentication, authorization, integrity, and
confidentiality. confidentiality.
Authentication refers to confirming the identity of an originator for "Authentication" refers to confirming the identity of an originator
all datagrams received from the originator. Lack of authentication for all datagrams received from the originator. Lack of
of Diameter messages between the Diameter peers can jeopardize the authentication of Diameter messages between the Diameter peers can
fundamental service of the peering network elements. A consequence jeopardize the fundamental service of the peering network elements.
of not authenticating the message sender by the recipient would be A consequence of not authenticating the message sender by the
that an attacker could spoof the identity of a "legitimate" recipient would be that an attacker could spoof the identity of a
authorizing entity in order to change the behavior of the receiver. "legitimate" authorizing entity in order to change the behavior of
An attacker could for example launch a denial of service attack by the receiver. An attacker could, for example, launch a DoS attack by
setting the maximum number of bindings for a session on the NAT- setting the maximum number of bindings for a session on the NAT
device to zero; provision bindings on a NAT-device which include IP- device to zero; provisioning bindings on a NAT device that includes
addresses already in use in other parts of the network; or request IP addresses already in use in other parts of the network; or
session termination of the Diameter session and hamper an endpoint's requesting session termination of the Diameter session and hampering
(i.e. a user's) connectivity. Lack of authentication of a NAT-device an endpoint's (i.e., a user's) connectivity. Lack of authentication
to a NAT-controller could lead to situations where the NAT-device of a NAT device to a NAT controller could lead to situations where
could provide a wrong view of the resources (i.e. NAT-bindings). In the NAT device could provide a wrong view of the resources (i.e.,
addition, NAT Binding Predefined template on the NAT-device could be NAT-bindings). In addition, a NAT-binding Predefined template on the
configured differently than expected by the NAT-controller. Failing NAT device could be configured differently than expected by the NAT
of any of the two DNCA Diameter peers to provide the required controller. If either of the two DNCA Diameter peers fail to provide
credentials should be subject to logging. The corresponding logging the required credentials, the failure should be subject to logging.
infrastructure of the operator SHOULD be built in a way that it can The corresponding logging infrastructure of the operator SHOULD be
mitigate potential denial of service attacks resulting from large built in a way that it can mitigate potential DoS attacks resulting
amounts of logging events. This could include proper dimensioning of from large amounts of logging events. This could include proper
the logging infrastructure combined with policing the maximum amount dimensioning of the logging infrastructure combined with policing the
of logging events accepted by the logging system to a threshold which maximum amount of logging events accepted by the logging system to a
the system is known to be able to handle. threshold which the system is known to be able to handle.
Authorization refers to whether a particular authorizing entity is "Authorization" refers to whether a particular authorizing entity is
authorized to signal a network element requests for one or more authorized to signal a network element request for one or more
applications, adhering to a certain policy profile. Failing the applications, adhering to a certain policy profile. Failing the
authorization process might indicate a resource theft attempt or authorization process might indicate a resource theft attempt or
failure due to administrative and/or credential deficiencies. In failure due to administrative and/or credential deficiencies. In
either case, the network element should take the proper measures to either case, the network element should take the proper measures to
log such attempts. log such attempts.
Integrity is required to ensure that a Diameter message exchanged Integrity is required to ensure that a Diameter message exchanged
between the Diameter peers has not been maliciously altered by between the Diameter peers has not been maliciously altered by
intermediate devices. The result of a lack of data integrity intermediate devices. The result of a lack of data integrity
enforcement in an untrusted environment could be that an impostor enforcement in an untrusted environment could be that an impostor
will alter the messages exchanged between the peers. This could will alter the messages exchanged between the peers. This could
cause a change of behavior of the peers, including the potential of a cause a change of behavior of the peers, including the potential of a
denial of service. DoS.
Confidentiality protection of Diameter messages ensures that the Confidentiality protection of Diameter messages ensures that the
signaling data is accessible only to the authorized entities. When signaling data is accessible only to the authorized entities. When
signaling messages between the DNCA Diameter peers traverse untrusted signaling messages between the DNCA Diameter peers traverse untrusted
networks, lack of confidentiality will allow eavesdropping and networks, lack of confidentiality will allow eavesdropping and
traffic analysis. traffic analysis.
Diameter offers security mechanisms to deal with the functionality Diameter offers security mechanisms to deal with the functionality
demanded above. DNCA makes use of the capabilities offered by demanded above. DNCA makes use of the capabilities offered by
Diameter and the underlying transport protocols to deliver these Diameter and the underlying transport protocols to deliver these
requirements (see Section 5.1). If the DNCA communication traverses requirements (see Section 5.1). If the DNCA communication traverses
untrusted networks, messages between DNCA Diameter peers SHOULD be untrusted networks, messages between DNCA Diameter peers SHOULD be
secured using either IPsec or TLS. Please refer to [RFC3588], secured using either IPsec or TLS. Please refer to [RFC6733],
section 13 for details. DNCA Diameter peers SHOULD perform bilateral Section 13 for details. DNCA Diameter peers SHOULD perform bilateral
authentication, authorization as well as procedures to ensure authentication, authorization, as well as procedures to ensure
integrity and confidentiality of the information exchange. In integrity and confidentiality of the information exchange. In
addition the Session-Id chosen for a particular Diameter session addition, the Session-Id chosen for a particular Diameter session
SHOULD be chosen in a way that it is hard to guess in order to SHOULD be chosen in a way that it is hard to guess in order to
mitigate issues through potential message replay. mitigate issues through potential message replay.
DNCA Diameter peers SHOULD have a mutual trust setup. This document DNCA Diameter peers SHOULD have a mutual trust setup. This document
does not specify a mechanisms for authorization between the DNCA does not specify a mechanism for authorization between the DNCA
Diameter peers. The DNCA Diameter peers SHOULD be provided with Diameter peers. The DNCA Diameter peers SHOULD be provided with
sufficient information to make an authorization decision. The sufficient information to make an authorization decision. The
information can come from various sources, for example the peering information can come from various sources, for example, the peering
devices could store local authentication policy, listing the devices could store local authentication policy, listing the
identities of authorized peers. identities of authorized peers.
Any mechanism or protocol providing control of a NAT-device, and DNCA Any mechanism or protocol providing control of a NAT device, and DNCA
is an example of such a control mechanism, could allow for misuse of is an example of such a control mechanism, could allow for misuse of
the NAT-device given that it enables the definition of per- the NAT device given that it enables the definition of per-
destination or per-source rules. Misuse could include anti- destination or per-source rules. Misuse could include anti-
competitive practices among providers, censorship, crime, etc. NAT- competitive practices among providers, censorship, crime, etc. NAT-
control could be used as a tool for preventing or redirecting access control could be used as a tool for preventing or redirecting access
to particular sites. For instance, by controlling the NAT bindings, to particular sites. For instance, by controlling the NAT-bindings,
one could ensure that endpoints aren't able to receive particular one could ensure that endpoints aren't able to receive particular
flows, or that those flows are redirected to a relay that snoops or flows, or that those flows are redirected to a relay that snoops or
tampers with traffic instead of directly forwarding the traffic to tampers with traffic instead of directly forwarding the traffic to
the intended endpoint. In addition one could set up a binding in a the intended endpoint. In addition, one could set up a binding in a
way that the source IP address used is one of a relay so that traffic way that the source IP address used is one of a relay so that traffic
coming back can be snooped on or interfered with. The operator also coming back can be snooped on or interfered with. The operator also
needs to consider security threats resulting from unplanned needs to consider security threats resulting from unplanned
termination of the DNCA session. Unplanned session termination, termination of the DNCA session. Unplanned session termination,
which could e.g. happen due to an attacker taking down the NAT- which could happen due to, e.g., an attacker taking down the NAT
controller, leads to the NAT-device cleaning up the state associated controller, leads to the NAT device cleaning up the state associated
with this session after a grace period. If the grace period is set with this session after a grace period. If the grace period is set
to zero, the endpoint will experience an immediate loss of to zero, the endpoint will experience an immediate loss of
connectivity to services reachable through the NAT-device following connectivity to services reachable through the NAT device following
the termination of the DNCA session.The protections on DNCA and its the termination of the DNCA session.The protections on DNCA and its
Diameter protocol exchanges don't prevent such abuses of NAT-control. Diameter protocol exchanges don't prevent such abuses of NAT-control.
Prevention of mis-use or mis-configuration of a NAT-device by an Prevention of misuse or misconfiguration of a NAT device by an
authorized NAT-controller is beyond the scope of this protocol authorized NAT controller is beyond the scope of this protocol
specification. A service provider deploying DNCA needs to make sure specification. A service provider deploying DNCA needs to make sure
that higher layer processes and procedures are put in place which that higher-layer processes and procedures are put in place that
allow them to detect and mitigate misuses. allow them to detect and mitigate misuses.
13. Examples 13. Examples
This section shows example DNCA message content and exchange. This section shows example DNCA message content and exchange.
13.1. DNCA Session Establishment Example 13.1. DNCA Session Establishment Example
Figure 15 depicts a typical call flow for DNCA session establishment. Figure 15 depicts a typical call flow for DNCA session establishment.
In this example, the NAT-controller: In this example, the NAT controller does the following:
a. requests a maximum of 100 NAT-bindings for the endpoint. a. requests a maximum of 100 NAT-bindings for the endpoint.
b. defines a static binding for a TCP connection which associates b. defines a static binding for a TCP connection that associates the
the internal IP-Address:Port 192.0.2.1:80 with the external IP- internal IP Address:Port 192.0.2.1:80 with the external IP
Address:Port 198.51.100.1:80 for the endpoint. Address:Port 198.51.100.1:80 for the endpoint.
c. requests the use of a preconfigured template called "local- c. requests the use of a preconfigured template called "local-
policy" while creating NAT-bindings for the endpoint. policy" while creating NAT-bindings for the endpoint.
endpoint NAT-Controller (within NAS) NAT-device endpoint NAT controller (within NAS) NAT device
| | | | | |
| | | | | |
| 1. Trigger | | | 1. Trigger | |
|--------------------------->| | |--------------------------->| |
| +-------------------------------------+ | | +-------------------------------------+ |
| | 2. Determine that NAT control | | | | 2. Determine that NAT control | |
| | is required for the endpoint | | | | is required for the endpoint | |
| +-------------------------------------+ | | +-------------------------------------+ |
| | | | | |
| | | | | |
| ................................... | ...................................
| .| 3. Diameter Base CER/CEA |. | .| 3. Diameter Base CER/CEA |.
| .|<----------------------------->|. | .|<----------------------------->|.
| ................................... | ...................................
| | | | | |
| | | | | |
| | 4. NCR | | | 4. NCR |
skipping to change at page 49, line 36 skipping to change at page 48, line 36
| | established | | established
| | | | | |
| | 6. NCA | | | 6. NCA |
| |<------------------------------| | |<------------------------------|
| | | | | |
| | | | | |
| 7. Data traffic | | 7. Data traffic |
|----------------------------------------------------------->| |----------------------------------------------------------->|
| | | | | |
| | | | | |
| | 8. NAT Bindings | | 8. NAT-bindings
| | created as per | | created as per
| | directives in the | | directives in the
| | DNCA session | | DNCA session
| | | | | |
Figure 15: Initial NAT control request and session establishment Figure 15: Initial NAT-Control-Request and
example Session Establishment Example
Detailed description of the steps shown in Figure 15: Detailed description of the steps shown in Figure 15:
1. The NAT-controller (co-located with the NAS here) creates state 1. The NAT controller (co-located with the NAS here) creates state
for an endpoint based on a trigger. This could for example be for an endpoint based on a trigger. This could, for example, be
the successful establishment of a Point-to-Point Protocol (PPP) the successful establishment of a Point-to-Point Protocol (PPP)
[RFC1661] access session. [RFC1661] access session.
2. Based on the configuration of the DNCA Diameter peer within the 2. Based on the configuration of the DNCA Diameter peer within the
NAT-controller, the NAT-controller determines that NAT-control is NAT controller, the NAT controller determines that NAT-control is
required and is to be enforced at a NAT-device. required and is to be enforced at a NAT device.
3. If there is no Diameter session already established with the DNCA 3. If there is no Diameter session already established with the DNCA
Diameter peer within NAT-device, a Diameter connection is Diameter peer within NAT device, a Diameter connection is
established and Diameter Base CER/CEA are exchanged. established and Diameter Base CER/CEA are exchanged.
4. The NAT-Controller creates an NCR message (see below) and sends 4. The NAT-Controller creates an NCR message (see below) and sends
it to the NAT-device. This example shows IPv4 to IPv4 address it to the NAT device. This example shows IPv4 to IPv4 address
and port translation. For IPv6 to IPv4 translation, the Framed- and port translation. For IPv6 to IPv4 translation, the Framed-
IP-Address AVP would be replaced by the Framed-IPv6-Address AVP IP-Address AVP would be replaced by the Framed-IPv6-Address AVP
with the value set to the IPv6 address of the endpoint. with the value set to the IPv6 address of the endpoint.
< NC-Request > ::= < Diameter Header: TBD.COM-CODE, REQ, PXY>
< NC-Request > ::= < Diameter Header: 330, REQ, PXY>
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Auth-Application-Id = <DNCA Application ID> Auth-Application-Id = <DNCA Application ID>
Origin-Host = "natC.example.com" Origin-Host = "natC.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Destination-Realm = "example.com" Destination-Realm = "example.com"
Destination-Host = "nat-device.example.com" Destination-Host = "nat-device.example.com"
NC-Request-Type = INITIAL_REQUEST NC-Request-Type = INITIAL_REQUEST
User-Name = "subscriber_example1" User-Name = "subscriber_example1"
Framed-IP-Address = "192.0.2.1" Framed-IP-Address = "192.0.2.1"
NAT-Control-Install = { NAT-Control-Install = {
skipping to change at page 50, line 43 skipping to change at page 49, line 44
Framed-IP-Address = "192.0.2.1" Framed-IP-Address = "192.0.2.1"
Port = 80 Port = 80
} }
NAT-External-Address = { NAT-External-Address = {
Framed-IP-Address = "198.51.100.1" Framed-IP-Address = "198.51.100.1"
Port = 80 Port = 80
} }
} }
Max-NAT-Bindings = 100 Max-NAT-Bindings = 100
NAT-Control-Binding-Template = "local-policy" NAT-Control-Binding-Template = "local-policy"
} }
5. The NAT-device establishes a DNCA session as it is able to comply 5. The NAT device establishes a DNCA session as it is able to comply
with the request. with the request.
6. The NAT-device sends an NCA to indicate the successful completion 6. The NAT device sends an NCA to indicate the successful completion
of the request. of the request.
<NC-Answer> ::= < Diameter Header: TBD.COM-CODE, PXY > <NC-Answer> ::= < Diameter Header: 330, PXY >
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Origin-Host = "nat-device.example.com" Origin-Host = "nat-device.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
NC-Request-Type = INITIAL_REQUEST NC-Request-Type = INITIAL_REQUEST
Result-Code = DIAMETER_SUCCESS Result-Code = DIAMETER_SUCCESS
7. The endpoint sends packets that reach the NAT-device. 7. The endpoint sends packets that reach the NAT device.
8. The NAT-device performs NAT for traffic received from the 8. The NAT device performs NAT for traffic received from the
endpoint with source address 192.0.2.1. Traffic with source IP- endpoint with source address 192.0.2.1. Traffic with source IP
address 192.0.2.1 and port 80 are translated to the external IP- address 192.0.2.1 and port 80 are translated to the external IP
address 198.51.100.1 and port 80. Traffic with source IP-address address 198.51.100.1 and port 80. Traffic with source IP address
192.0.2.1 and a source port different from 80 will be translated 192.0.2.1 and a source port different from 80 will be translated
to IP-address 198.51.100.1 and a port chosen by the NAT-device. to IP address 198.51.100.1 and a port chosen by the NAT device.
Note that this example assumes that the NAT-device follows Note that this example assumes that the NAT device follows
typical binding allocation rules for endpoints, in that only a typical binding allocation rules for endpoints, in that only a
single external IP-address is used for all traffic received from single external IP address is used for all traffic received from
a single IP-address of an endpoint. The NAT-device will allow a a single IP address of an endpoint. The NAT device will allow a
maximum of 100 NAT-bindings be created for the endpoint. maximum of 100 NAT-bindings be created for the endpoint.
13.2. DNCA Session Update with Port Style Example 13.2. DNCA Session Update with Port Style Example
This section gives an example for a DNCA session update: A new set of This section gives an example for a DNCA session update: A new set of
NAT-bindings is requested for an existing session. The request NAT-bindings is requested for an existing session. The request
contains a directive ( the "NAT-External-Port-Style" AVP set to contains a directive ( the "NAT-External-Port-Style" AVP set to
FOLLOW_INTERNAL_PORT_STYLE) that directs the NAT-device to maintain FOLLOW_INTERNAL_PORT_STYLE) that directs the NAT device to maintain
port-sequence and port-oddity for the newly created NAT-bindings. In port-sequence and port-oddity for the newly created NAT-bindings. In
the example shown, the internal ports are UDP port 1036 and 1037. the example shown, the internal ports are UDP port 1036 and 1037.
The NAT-device follows the directive selects the external ports The NAT device follows the directive selects the external ports
accordingly. The NAT-device would for example create a mapping of accordingly. The NAT device would, for example, create a mapping of
192.0.2.1:1036 to 198.51.100.1:5056 and 192.0.2.1:1037 to 192.0.2.1:1036 to 198.51.100.1:5056 and 192.0.2.1:1037 to
198.51.100.1:5057, thereby maintaining port oddity (1036->5056, 198.51.100.1:5057, thereby maintaining port oddity (1036->5056,
1037->5057) and sequence ( the consecutive internal ports 1036 and 1037->5057) and sequence ( the consecutive internal ports 1036 and
1037 map to the consecutive external ports 5056 and 5057). 1037 map to the consecutive external ports 5056 and 5057).
< NC-Request > ::= < Diameter Header: TBD.COM-CODE, REQ, PXY> < NC-Request > ::= < Diameter Header: 330, REQ, PXY>
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Auth-Application-Id = <DNCA Application ID> Auth-Application-Id = <DNCA Application ID>
Origin-Host = "natC.example.com" Origin-Host = "natC.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Destination-Realm = "example.com" Destination-Realm = "example.com"
Destination-Host = "nat-device.example.com" Destination-Host = "nat-device.example.com"
NC-Request-Type = UPDATE_REQUEST NC-Request-Type = UPDATE_REQUEST
NAT-Control-Install = { NAT-Control-Install = {
NAT-Control-Definition = { NAT-Control-Definition = {
Protocol = UDP Protocol = UDP
skipping to change at page 52, line 37 skipping to change at page 51, line 37
Port = 1036 Port = 1036
} }
} }
NAT-External-Port- NAT-External-Port-
Style = FOLLOW_INTERNAL_PORT_STYLE Style = FOLLOW_INTERNAL_PORT_STYLE
} }
13.3. DNCA Session Query Example 13.3. DNCA Session Query Example
This section shows an example for DNCA session query for a subscriber This section shows an example for DNCA session query for a subscriber
whose internal IP-Address is 192.0.2.1. whose internal IP Address is 192.0.2.1.
< NC-Request > ::= < Diameter Header: TBD.COM-CODE, REQ, PXY> < NC-Request > ::= < Diameter Header: 330, REQ, PXY>
Auth-Application-Id = <DNCA Application ID> Auth-Application-Id = <DNCA Application ID>
Origin-Host = "natC.example.com" Origin-Host = "natC.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Destination-Realm = "example.com" Destination-Realm = "example.com"
Destination-Host = "nat-device.example.com" Destination-Host = "nat-device.example.com"
NC-Request-Type = QUERY_REQUEST NC-Request-Type = QUERY_REQUEST
Framed-IP-Address = "192.0.2.1" Framed-IP-Address = "192.0.2.1"
The NAT-device constructs an NCA to report all currently active NAT- The NAT device constructs an NCA to report all currently active NAT-
bindings whose internal address is 192.0.2.1. bindings whose internal address is 192.0.2.1.
<NC-Answer> ::= < Diameter Header: TBD.COM-CODE, PXY > <NC-Answer> ::= < Diameter Header: 330, PXY >
Origin-Host = "nat-device.example.com" Origin-Host = "nat-device.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
NC-Request-Type = QUERY_REQUEST NC-Request-Type = QUERY_REQUEST
NAT-Control-Definition = { NAT-Control-Definition = {
Protocol = TCP Protocol = TCP
Direction = OUT Direction = OUT
NAT-Internal-Address = { NAT-Internal-Address = {
Framed-IP-Address = "192.0.2.1" Framed-IP-Address = "192.0.2.1"
Port = 80 Port = 80
} }
skipping to change at page 53, line 47 skipping to change at page 52, line 47
Direction = OUT Direction = OUT
NAT-Internal-Address = { NAT-Internal-Address = {
Framed-IP-Address = "192.0.2.1" Framed-IP-Address = "192.0.2.1"
Port = 1037 Port = 1037
} }
NAT-External-Address = { NAT-External-Address = {
Framed-IP-Address = "198.51.100.1" Framed-IP-Address = "198.51.100.1"
Port = 5057 Port = 5057
} }
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
} }
13.4. DNCA Session Termination Example 13.4. DNCA Session Termination Example
In this example the NAT-controller decides to terminate the In this example the NAT controller decides to terminate the
previously established DNCA session. This could for example be the previously established DNCA session. This could, for example, be the
case as a result of an access session (e.g. a PPP session) associated case as a result of an access session (e.g., a PPP session)
with an endpoint been torn down. associated with an endpoint having been torn down.
NAT-Controller NAT-device NAT controller NAT device
| | | |
| | | |
+--------------+ | +--------------+ |
| 1. Trigger | | | 1. Trigger | |
+--------------+ | +--------------+ |
| | | |
| | | |
| 2. STR | | 2. STR |
|-------------------------------------->| |-------------------------------------->|
| | | |
skipping to change at page 54, line 34 skipping to change at page 53, line 39
|-------------------------------------->| |-------------------------------------->|
| | | |
| | | |
| 6. DNCA bindings | 6. DNCA bindings
| and session cleanup | and session cleanup
| | | |
| 7. STA | | 7. STA |
|<--------------------------------------| |<--------------------------------------|
| | | |
Figure 20: NAT control session termination example Figure 20: NAT Control Session Termination Example
The following steps describe the sequence of events for tearing down The following steps describe the sequence of events for tearing down
the DNCA session in the example above: the DNCA session in the example above:
1. The NAT-controller receives a trigger that a DNCA session 1. The NAT controller receives a trigger that a DNCA session
associated with a specific endpoint should be terminated. An associated with a specific endpoint should be terminated. An
example event could be the termination of the PPP [RFC1661] example event could be the termination of the PPP [RFC1661]
access session to an endpoint in a NAS. The NAS correspondingly access session to an endpoint in a NAS. The NAS correspondingly
triggers the NAT-controller request tear-down of the associated triggers the NAT controller request to tear down the associated
DNCA session. DNCA session.
2. The NAT-controller creates the required NCR message and sends it 2. The NAT controller creates the required NCR message and sends it
to the NAT-device: to the NAT device:
< STR > ::= < Diameter Header: 275, REQ, PXY> < STR > ::= < Diameter Header: 275, REQ, PXY>
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Auth-Application-Id = <DNCA Application ID> Auth-Application-Id = <DNCA Application ID>
Origin-Host = "natC.example.com" Origin-Host = "natC.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Destination-Realm = "example.com" Destination-Realm = "example.com"
Destination-Host = "nat-device.example.com" Destination-Host = "nat-device.example.com"
Termination-Cause = DIAMETER_LOGOUT Termination-Cause = DIAMETER_LOGOUT
3. The NAT-device looks up the DNCA session based on the Session-Id 3. The NAT device looks up the DNCA session based on the Session-Id
AVP and finds a previously established active session. AVP and finds a previously established active session.
4. The NAT-device reports all NAT-bindings established for that 4. The NAT device reports all NAT-bindings established for that
subscriber using an ACR: subscriber using an ACR:
< ACR > ::= < Diameter Header: 271, REQ, PXY> < ACR > ::= < Diameter Header: 271, REQ, PXY>
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Auth-Application-Id = <DNCA Application ID> Auth-Application-Id = <DNCA Application ID>
Origin-Host = "nat-device.example.com" Origin-Host = "nat-device.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Destination-Realm = "example.com" Destination-Realm = "example.com"
Destination-Host = "natC.example.com" Destination-Host = "natC.example.com"
Accounting-Record-Type = STOP_RECORD Accounting-Record-Type = STOP_RECORD
Accounting-Record-Number = 1 Accounting-Record-Number = 1
skipping to change at page 55, line 44 skipping to change at page 55, line 5
Port = 5001 Port = 5001
} }
NAT-External-Address = { NAT-External-Address = {
Framed-IP-Address = "198.51.100.1" Framed-IP-Address = "198.51.100.1"
Port = 7777 Port = 7777
} }
} }
NAT-Control-Binding-Status = Removed NAT-Control-Binding-Status = Removed
} }
5. The NAT-controller receives and processes the ACR as per its 5. The NAT controller receives and processes the ACR as per its
configuration. It responds with an ACA to the NAT-device. configuration. It responds with an ACA to the NAT device.
<ACA> ::= < Diameter Header: 271, PXY > <ACA> ::= < Diameter Header: 271, PXY >
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Origin-Host = "natC.example.com" Origin-Host = "natC.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Result-Code = DIAMETER_SUCCESS Result-Code = DIAMETER_SUCCESS
Accounting-Record-Type = STOP_RECORD Accounting-Record-Type = STOP_RECORD
Accounting-Record-Number = 1 Accounting-Record-Number = 1
6. On receipt of the ACA the NAT-device cleans up all NAT-bindings 6. On receipt of the ACA the NAT device cleans up all NAT-bindings
and associated session state for the endpoint. and associated session state for the endpoint.
7. NAT-device sends an STA. On receipt of the STA the NAT- 7. NAT device sends an STA. On receipt of the STA the NAT
controller will clean up the corresponding session state. controller will clean up the corresponding session state.
<STA> ::= < Diameter Header: 275, PXY > <STA> ::= < Diameter Header: 275, PXY >
Session-Id = "natC.example.com:33041;23432;" Session-Id = "natC.example.com:33041;23432;"
Origin-Host = "nat-device.example.com" Origin-Host = "nat-device.example.com"
Origin-Realm = "example.com" Origin-Realm = "example.com"
Result-Code = DIAMETER_SUCCESS Result-Code = DIAMETER_SUCCESS
14. Acknowledgements 14. Acknowledgements
The authors would like to thank Jari Arkko, Wesley Eddy, Stephen The authors would like to thank Jari Arkko, Wesley Eddy, Stephen
Farrell, Miguel A. Garcia, David Harrington, Jouni Korhonen, Matt Farrell, Miguel A. Garcia, David Harrington, Jouni Korhonen, Matt
Lepinski, Avi Lior, Chris Metz, Pallavi Mishra, Lionel Morand, Robert Lepinski, Avi Lior, Chris Metz, Pallavi Mishra, Lionel Morand, Robert
Sparks, Martin Stiemerling, Dave Thaler, Hannes Tschofenig, Sean Sparks, Martin Stiemerling, Dave Thaler, Hannes Tschofenig, Sean
Turner, Shashank Vikram, Greg Weber, and Glen Zorn for their input on Turner, Shashank Vikram, Greg Weber, and Glen Zorn for their input on
this document. this document.
15. Change History (to be removed prior to publication as an RFC) 15. References
Changes from -00 to -01
a. new values for Result-Code AVP used - instead of Experimental-
Result AVP
b. added support for transport specific binding (UDP/TCP)
c. added support for twice-NAT
d. clarified the use of the two different types of query-requests
Changes from -01 to -02
a. Reference to pull mode removed, session initiation event
clarified in section 4.1
b. added Redirect-* AVPs in NCA command
c. Removed reference to Called-Station-Id AVP in NCR command
d. Editorial changes
e. added support for bindings providing AFT (NAT64)
Changes from -02 to -03
a. Editorial changes
Changes from -03 to -04
a. Editorial changes suggested in WG last call review
b. Removed NCR Request type terminate and replaced with STR
c. All references to Auth-Session-State are removed and a new
section to describe FSM for Manager and Agent has been added
d. Clarified reuse of External address and address pools among
multiple subscribers
Changes from -04 to -05
a. Removed references to Large Scale NAT as per review comments
Changes from -05 to -06
a. Editorial changes
Changes from -06 to -07
a. Added a note in section 4.3 stating the state of pre-existing
bindings on update failure
b. Security considerations are made consistent between sections 5.1
and 12
c. Editorial changes
Changes from -07 to -08
a. Added section 4.6 to describe session abort
b. Editorial changes
c. Nomenclature change: From DNCA Agent/Manager to DNCA Diameter
peers identifying the location where they reside (NAT-controller
or NAT-device)
d. IANA consideration Section format changes
e. Updated security section (included considerations directly,
rather than referring to Diameter QoS similarities).
Changes from -08 to -09
a. expanded on the need for an SP controlling the maximum number of
bindings of an endpoint (see introduction section)
b. added a paragraph in the security section outlining general mis-
uses of NAT-control (non specific to DNCA), with DNCA being an
example of such a NAT-control protocol
c. editorial changes
Changes from -09 to -10
a. Section 4 and security considerations updated with RFC 2119
language
b. NAT-External-Port-Style AVP added to aid external port oddity
requirement as per MIDCOM framework
c. NAT related RFCs added in normative reference
d. Section 13 added to provide example DNCA message exchange flows
e. Added a description to provide DNCA comparison with MIDCOM
f. n:1 deployment model for NAT-controllers and NAT-devices
explicitly specified
g. editorial changes as per IESG DISCUSS comments
Changes from -10 to -11
a. clarified DNCA session query to be done after Diameter session is
established
b. Section 4.4 Session Termination updated to specify resource
cleanup at NAT-Device upon session termination
c. Removed Framed-IP-Netmask AVP from NAT-External-Address as
external address is fully defined by Framed-IP-Address AVP
d. Updated Section 12 to highlight Session-Id to be chosen such that
it is hard to guess
e. editorial changes as per IESG DISCUSS
Changes from -11 to -12
a. endpoint replaces references to end point and user and defines
what Endpoint means in this draft
b. editorial changes as per IESG DISCUSS
Changes from -12 to -13
a. Section 4.3 session query updated to use NAT-External-Address for
external IP-address based query
Changes from -13 to -14
a. Added NAT-External-Address in NC-request for session query by
external IP-address
b. Reordered all mandatory AVPs in NCR and NCA to appear before
optional AVPs
Changes from -14 to -15
a. As part of IESG discuss - clarified that multiple methods if used
along with DNCA for NAT control should be configured to prevent
conflict.
b. Clarified misuse of NAT-device by a Diameter authorized NAT-
controller using DNCA is beyond the scope of this protocol
specification.
c. Editorial updates.
Changes from -15 to -16
a. Extended section covering case of a single NAT-device controlled
by multiple NAT-ontrollers which use different protocols for
configuring the NAT-device.
b. Added NAT-device state cleanup in case of unexpected/unplanned
termination of Diameter session or application either on NAT-
controller or NAT-device.
c. Added MAX_BINDINGS_SET_FAILURE failure case (for those scenarios
where the maximum number of bindings cannot be set by the
controller)
Change from -16 to -17
a. Clarified that the endpoint identifier Framed-IP-Address and the
internal address in NAT-Internal-Address specified to install
NAT-bindings for the session MUST match.
16. References
16.1. Normative References 15.1. Normative References
[ETSIES283034] [ETSIES283034] ETSI, "Telecommunications and Internet Converged
ETSI, "Telecommunications and Internet Converged Services Services and Protocols for Advanced Networks
and Protocols for Advanced Networks (TISPAN),Network (TISPAN), Network Attachment Sub-System (NASS), e4
Attachment Sub-System (NASS),e4 interface based on the interface based on the Diameter protocol.",
Diameter protocol.", September 2008. September 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
Arkko, "Diameter Base Protocol", RFC 3588, September 2003. "Diameter Network Access Server Application",
RFC 4005, August 2005.
[RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, [RFC4675] Congdon, P., Sanchez, M., and B. Aboba, "RADIUS
"Diameter Network Access Server Application", RFC 4005, Attributes for Virtual LAN and Priority Support",
August 2005. RFC 4675, September 2006.
[RFC4675] Congdon, P., Sanchez, M., and B. Aboba, "RADIUS Attributes [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing
for Virtual LAN and Priority Support", RFC 4675, an IANA Considerations Section in RFCs", BCP 26,
September 2006. RFC 5226, May 2008.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M.,
IANA Considerations Section in RFCs", BCP 26, RFC 5226, Jones, M., and A. Lior, "Traffic Classification and
May 2008. Quality of Service (QoS) Attributes for Diameter",
RFC 5777, February 2010.
[RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M., [RFC6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
and A. Lior, "Traffic Classification and Quality of "Diameter Base Protocol", RFC 6733, October 2012.
Service (QoS) Attributes for Diameter", RFC 5777,
February 2010.
16.2. Informative References 15.2. Informative References
[I-D.ietf-behave-lsn-requirements] [CGN-REQS] Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa,
Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A., A., and H. Ashida, "Common requirements for Carrier
and H. Ashida, "Common requirements for Carrier Grade NATs Grade NATs (CGNs)", Work in Progress, September 2012.
(CGNs)", draft-ietf-behave-lsn-requirements-05 (work in
progress), November 2011.
[RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, [RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)",
RFC 1661, July 1994. STD 51, RFC 1661, July 1994.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations", Translator (NAT) Terminology and Considerations",
RFC 2663, August 1999. RFC 2663, August 1999.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network [RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022, Address Translator (Traditional NAT)", RFC 3022,
January 2001. January 2001.
[RFC3303] Srisuresh, P., Kuthan, J., Rosenberg, J., Molitor, A., and [RFC3303] Srisuresh, P., Kuthan, J., Rosenberg, J., Molitor,
A. Rayhan, "Middlebox communication architecture and A., and A. Rayhan, "Middlebox communication
framework", RFC 3303, August 2002. architecture and framework", RFC 3303, August 2002.
[RFC3304] Swale, R., Mart, P., Sijben, P., Brim, S., and M. Shore, [RFC3304] Swale, R., Mart, P., Sijben, P., Brim, S., and M.
"Middlebox Communications (midcom) Protocol Requirements", Shore, "Middlebox Communications (midcom) Protocol
RFC 3304, August 2002. Requirements", RFC 3304, August 2002.
[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, Protocol (SNMP) Management Frameworks", STD 62,
December 2002. RFC 3411, December 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
[RFC4097] Barnes, M., "Middlebox Communications (MIDCOM) Protocol [RFC4097] Barnes, M., "Middlebox Communications (MIDCOM)
Evaluation", RFC 4097, June 2005. Protocol Evaluation", RFC 4097, June 2005.
[RFC5189] Stiemerling, M., Quittek, J., and T. Taylor, "Middlebox [RFC5189] Stiemerling, M., Quittek, J., and T. Taylor,
Communication (MIDCOM) Protocol Semantics", RFC 5189, "Middlebox Communication (MIDCOM) Protocol
March 2008. Semantics", RFC 5189, March 2008.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011. Algorithm", RFC 6145, April 2011.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum,
NAT64: Network Address and Protocol Translation from IPv6 "Stateful NAT64: Network Address and Protocol
Clients to IPv4 Servers", RFC 6146, April 2011. Translation from IPv6 Clients to IPv4 Servers",
RFC 6146, April 2011.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011. RFC 6241, June 2011.
Authors' Addresses Authors' Addresses
Frank Brockners Frank Brockners
Cisco Cisco
Hansaallee 249, 3rd Floor Hansaallee 249, 3rd Floor
DUESSELDORF, NORDRHEIN-WESTFALEN 40549 Duesseldorf, Nordrhein-Westfalen 40549
Germany Germany
Email: fbrockne@cisco.com EMail: fbrockne@cisco.com
Shwetha Bhandari Shwetha Bhandari
Cisco Cisco
Cessna Business Park, Sarjapura Marathalli Outer Ring Road Cessna Business Park, Sarjapura Marathalli Outer Ring Road
Bangalore, KARNATAKA 560 087 Bangalore, Karnataka 560 087
India India
Email: shwethab@cisco.com EMail: shwethab@cisco.com
Vaneeta Singh Vaneeta Singh
18, Cambridge Road 18, Cambridge Road
Bangalore 560008 Bangalore 560008
India India
Email: vaneeta.singh@gmail.com EMail: vaneeta.singh@gmail.com
Victor Fajardo Victor Fajardo
Telcordia Technologies Telcordia Technologies
1 Telcordia Drive #1S-222 1 Telcordia Drive #1S-222
Piscataway, NJ 08854 Piscataway, NJ 08854
USA USA
Email: vf0213@gmail.com EMail: vf0213@gmail.com
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