draft-ietf-dime-nat-control-07.txt   draft-ietf-dime-nat-control-08.txt 
Internet Engineering Task Force F. Brockners Internet Engineering Task Force F. Brockners
Internet-Draft S. Bhandari Internet-Draft S. Bhandari
Intended status: Standards Track Cisco Intended status: Standards Track Cisco
Expires: August 20, 2011 V. Singh Expires: January 1, 2012 V. Singh
V. Fajardo V. Fajardo
Telcordia Technologies Telcordia Technologies
February 16, 2011 June 30, 2011
Diameter Network Address and Port Translation Control Application Diameter Network Address and Port Translation Control Application
draft-ietf-dime-nat-control-07 draft-ietf-dime-nat-control-08
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 cope with IPv4-address space Translators, which are added to networks to cope with IPv4-address
completion. This Diameter application allows external devices to space completion. This Diameter application allows external devices
configure and manage a Network Address Translator device - expanding to configure and manage a Network Address Translator device -
the existing Diameter-based AAA and policy control capabilities with expanding the existing Diameter-based AAA and policy control
a Network Address Translators and Network Address and Port capabilities with a Network Address Translators and Network Address
Translators control component. These external devices can be network and Port Translators control component. These external devices can
elements in the data plane such as a Network Access Server, or can be be network elements in the data plane such as a Network Access
more centralized control plane devices such as AAA-servers. This Server, or can be more centralized control plane devices such as AAA-
Diameter application establishes a context to commonly identify and servers. This Diameter application establishes a context to commonly
manage endpoints on a gateway or server, and a Network Address identify and manage endpoints on a gateway or server, and a Network
Translator and Network Address and Port Translator device. This Address Translator and Network Address and Port Translator device.
includes, for example, the control of the total number of Network This includes, for example, the control of the total number of
Address Translator bindings allowed or the allocation of a specific Network Address Translator bindings allowed or the allocation of a
Network Address Translator binding for a particular endpoint. In specific Network Address Translator binding for a particular
addition, it allows Network Address Translator devices to provide endpoint. In addition, it allows Network Address Translator devices
information relevant to accounting purposes. to provide information relevant to accounting purposes.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 20, 2011. This Internet-Draft will expire on January 1, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 3, line 14 skipping to change at page 3, line 14
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Deployment Framework . . . . . . . . . . . . . . . . . . . . . 7 3. Deployment Framework . . . . . . . . . . . . . . . . . . . . . 7
3.1. Deployment Scenario . . . . . . . . . . . . . . . . . . . 7 3.1. Deployment Scenario . . . . . . . . . . . . . . . . . . . 7
3.2. Diameter NAPT Control Application Overview . . . . . . . . 8 3.2. Diameter NAPT Control Application Overview . . . . . . . . 8
3.3. Deployment Scenarios For DNCA . . . . . . . . . . . . . . 9 3.3. Deployment Scenarios For DNCA . . . . . . . . . . . . . . 9
4. DNCA Session Establishment and Management . . . . . . . . . . 11 4. DNCA Session Establishment and Management . . . . . . . . . . 11
4.1. Parties Involved . . . . . . . . . . . . . . . . . . . . . 11 4.1. Session Establishment . . . . . . . . . . . . . . . . . . 11
4.2. Session Establishment . . . . . . . . . . . . . . . . . . 11 4.2. Session Re-Authorization . . . . . . . . . . . . . . . . . 14
4.3. Session Re-Authorization . . . . . . . . . . . . . . . . . 13 4.3. Session and Binding Query . . . . . . . . . . . . . . . . 16
4.4. Session and Binding Query . . . . . . . . . . . . . . . . 15 4.4. Session Termination . . . . . . . . . . . . . . . . . . . 18
4.5. Session Termination . . . . . . . . . . . . . . . . . . . 17 4.5. Session Abort . . . . . . . . . . . . . . . . . . . . . . 19
4.6. DNCA Manager and Agent Failures . . . . . . . . . . . . . 18 4.6. Failure cases of the DNCA Diameter peers . . . . . . . . . 20
5. Use Of The Diameter Base Protocol . . . . . . . . . . . . . . 18 5. Use Of The Diameter Base Protocol . . . . . . . . . . . . . . 21
5.1. Securing Diameter Messages . . . . . . . . . . . . . . . . 19 5.1. Securing Diameter Messages . . . . . . . . . . . . . . . . 21
5.2. Accounting Functionality . . . . . . . . . . . . . . . . . 19 5.2. Accounting Functionality . . . . . . . . . . . . . . . . . 22
5.3. Use Of Sessions . . . . . . . . . . . . . . . . . . . . . 19 5.3. Use Of Sessions . . . . . . . . . . . . . . . . . . . . . 22
5.4. Routing Considerations . . . . . . . . . . . . . . . . . . 19 5.4. Routing Considerations . . . . . . . . . . . . . . . . . . 22
5.5. Advertising Application Support . . . . . . . . . . . . . 19 5.5. Advertising Application Support . . . . . . . . . . . . . 22
6. DNCA Commands . . . . . . . . . . . . . . . . . . . . . . . . 20 6. DNCA Commands . . . . . . . . . . . . . . . . . . . . . . . . 22
6.1. NAT-Control Request (NCR) Command . . . . . . . . . . . . 20 6.1. NAT-Control Request (NCR) Command . . . . . . . . . . . . 22
6.2. NAT-Control Answer (NCA) Command . . . . . . . . . . . . . 21 6.2. NAT-Control Answer (NCA) Command . . . . . . . . . . . . . 23
7. NAT Control Application Session State Machine . . . . . . . . 21 7. NAT Control Application Session State Machine . . . . . . . . 24
8. DNCA AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . 24 8. DNCA AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 24 8.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 27
8.2. Additional Result-Code AVP Values . . . . . . . . . . . . 25 8.2. Additional Result-Code AVP Values . . . . . . . . . . . . 28
8.2.1. Success . . . . . . . . . . . . . . . . . . . . . . . 25 8.2.1. Success . . . . . . . . . . . . . . . . . . . . . . . 28
8.2.2. Transient Failures . . . . . . . . . . . . . . . . . . 25 8.2.2. Transient Failures . . . . . . . . . . . . . . . . . . 28
8.2.3. Permanent Failures . . . . . . . . . . . . . . . . . . 26 8.2.3. Permanent Failures . . . . . . . . . . . . . . . . . . 29
8.3. Reused NASREQ Diameter Application AVPs . . . . . . . . . 27 8.3. Reused NASREQ Diameter Application AVPs . . . . . . . . . 30
8.4. Reused from RFC 4675 . . . . . . . . . . . . . . . . . . . 27 8.4. Reused AVPs from RFC 4675 . . . . . . . . . . . . . . . . 30
8.5. Reused from Diameter QoS Application . . . . . . . . . . . 27 8.5. Reused AVPs from Diameter QoS Application . . . . . . . . 31
8.6. Reused from ETSI ES 283 034, e4 Diameter Application . . . 28 8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter
8.7. DNCA Defined AVPs . . . . . . . . . . . . . . . . . . . . 29 Application . . . . . . . . . . . . . . . . . . . . . . . 31
8.7.1. NC-Request-Type AVP . . . . . . . . . . . . . . . . . 29 8.7. DNCA Defined AVPs . . . . . . . . . . . . . . . . . . . . 32
8.7.2. NAT-Control-Install AVP . . . . . . . . . . . . . . . 30 8.7.1. NC-Request-Type AVP . . . . . . . . . . . . . . . . . 32
8.7.3. NAT-Control-Remove AVP . . . . . . . . . . . . . . . . 30 8.7.2. NAT-Control-Install AVP . . . . . . . . . . . . . . . 33
8.7.4. NAT-Control-Definition AVP . . . . . . . . . . . . . . 30 8.7.3. NAT-Control-Remove AVP . . . . . . . . . . . . . . . . 33
8.7.5. NAT-Internal-Address AVP . . . . . . . . . . . . . . . 31 8.7.4. NAT-Control-Definition AVP . . . . . . . . . . . . . . 33
8.7.6. NAT-External-Address AVP . . . . . . . . . . . . . . . 31 8.7.5. NAT-Internal-Address AVP . . . . . . . . . . . . . . . 34
8.7.7. Max-NAT-Bindings . . . . . . . . . . . . . . . . . . . 32 8.7.6. NAT-External-Address AVP . . . . . . . . . . . . . . . 34
8.7.8. NAT-Control-Binding-Rule AVP . . . . . . . . . . . . . 32 8.7.7. Max-NAT-Bindings . . . . . . . . . . . . . . . . . . . 35
8.7.9. Duplicate-Session-Id AVP . . . . . . . . . . . . . . . 32 8.7.8. NAT-Control-Binding-Rule AVP . . . . . . . . . . . . . 35
9. Accounting Commands . . . . . . . . . . . . . . . . . . . . . 32 8.7.9. Duplicate-Session-Id AVP . . . . . . . . . . . . . . . 35
9.1. NAT Control Accounting Messages . . . . . . . . . . . . . 33 9. Accounting Commands . . . . . . . . . . . . . . . . . . . . . 35
9.2. NAT Control Accounting AVPs . . . . . . . . . . . . . . . 33 9.1. NAT Control Accounting Messages . . . . . . . . . . . . . 36
9.2.1. NAT-Control-Record . . . . . . . . . . . . . . . . . . 33 9.2. NAT Control Accounting AVPs . . . . . . . . . . . . . . . 36
9.2.2. NAT-Control-Binding-Status . . . . . . . . . . . . . . 33 9.2.1. NAT-Control-Record . . . . . . . . . . . . . . . . . . 36
9.2.3. Current-NAT-Bindings . . . . . . . . . . . . . . . . . 34 9.2.2. NAT-Control-Binding-Status . . . . . . . . . . . . . . 36
10. AVP Occurrence Table . . . . . . . . . . . . . . . . . . . . . 34 9.2.3. Current-NAT-Bindings . . . . . . . . . . . . . . . . . 37
10. AVP Occurrence Table . . . . . . . . . . . . . . . . . . . . . 37
10.1. DNCA AVP Table for NAT Control Initial and Update 10.1. DNCA AVP Table for NAT Control Initial and Update
Requests . . . . . . . . . . . . . . . . . . . . . . . . . 34 Requests . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.2. DNCA AVP Table for Session Query request . . . . . . . . . 35 10.2. DNCA AVP Table for Session Query request . . . . . . . . . 38
10.3. DNCA AVP Table for Accounting Message . . . . . . . . . . 35 10.3. DNCA AVP Table for Accounting Message . . . . . . . . . . 38
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38
11.1. Command Codes . . . . . . . . . . . . . . . . . . . . . . 36 11.1. Application Identifier . . . . . . . . . . . . . . . . . . 39
11.2. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 36 11.2. Command Codes . . . . . . . . . . . . . . . . . . . . . . 39
11.3. AVP Values . . . . . . . . . . . . . . . . . . . . . . . . 36 11.3. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 39
11.3.1. Result-Code AVP Values . . . . . . . . . . . . . . . . 37 11.4. Result-Code AVP Values . . . . . . . . . . . . . . . . . . 39
11.4. Application IDs . . . . . . . . . . . . . . . . . . . . . 37 11.5. NC-Request-Type AVP . . . . . . . . . . . . . . . . . . . 39
12. Security Considerations . . . . . . . . . . . . . . . . . . . 38 11.6. NAT-Control-Binding-Status AVP . . . . . . . . . . . . . . 39
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 38 12. Security Considerations . . . . . . . . . . . . . . . . . . . 40
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 41
14. Change History (to be removed prior to publication as an 14. Change History (to be removed prior to publication as an
RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40 15. Normative References . . . . . . . . . . . . . . . . . . . . . 43
15.1. Normative References . . . . . . . . . . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 43
15.2. Informative References . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction 1. Introduction
Internet service providers have started to deploy Network Address Internet service providers have started to deploy Network Address
Translators (NATs) and Network Address and Port Translators (NAPTs) Translators (NATs) and Network Address and Port Translators (NAPTs)
at the edge of their networks to deal with the depletion of available in their networks to deal with the depletion of available public IPv4
public IPv4 addresses. This document defines a Diameter application addresses. This document defines a Diameter application allowing
for providers deploying such NAT and NAPT devices. The use of a providers to control the behavior of these NAT and NAPT devices. The
Diameter application allows for simple integration into the existing use of a Diameter application allows for simple integration into the
Authentication, Authorization and Accounting (AAA) environment of a existing Authentication, Authorization and Accounting (AAA)
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 subscriber or end point. to an individual subscriber or end point.
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 pre-defined NAT binding: Both the internal and
external IP address and port pair are specified within the external IP address and port pair are specified within the
request. In some deployment cases, such as access to a web- request. Some deployment cases, such as access to a web-
server within a user's home network with IP address and port, server within a user's home network with IP address and port,
benefit from statically configured bindings. 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 requestor. 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 either be pre-
assigned at the NAPT/NAT, or specified within a request. If pre- assigned at the NAPT/NAT device, or specified within a request.
assigned address pools are used, a request needs to include a If pre-assigned address pools are used, a request needs to
reference to identify the pool. Otherwise, the request contains include a reference to identify the pool. Otherwise, the request
a description of the IP address pool(s) to be used; for example, contains a description of the IP address pool(s) to be used; for
list of IP-subnets. Such External address pools can be used to example, a list of IP-subnets. Such external address pools can
select external IP address in NAPT/NAT bindings for multiple be used to select the external IP address in NAPT/NAT bindings
subscribers. for multiple subscribers.
4. Generates reports and accounting records: Reports established 4. Generates reports and accounting records: Reports established
bindings for a particular user. The collected information is bindings for a particular user. 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). functionality (see item 4).
6. Identifies a subscriber or endpoint on multiple network devices 6. Identifies a subscriber or endpoint on multiple network devices
(NAPT or NAT 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 or a set
of classifiers, such as IP address, Virtual Local Area Network of classifiers, such as IP address, Virtual Local Area Network
(VLAN) identifier, or interface identifier which uniquely (VLAN) identifier, or interface identifier which uniquely
identify the traffic associated with a particular global endpoint identify the traffic associated with a particular global
endpoint.
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 4 to 8 cover DNCA specifics, with
Section 4 describing session management, Section 5 the use of the Section 4 describing session management, Section 5 the use of the
Diameter base protocol, Section 6 new commands, Section 7 AVPs used, Diameter base protocol, Section 6 new commands, Section 7 AVPs used,
and Section 8 accounting aspects. Section 9 presents an AVP and Section 8 accounting aspects. Section 9 presents an AVP
occurance table. IANA and security considerations are addressed in occurence table. IANA and security considerations are addressed in
Sections 10 and 11. Sections 10 and 11.
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 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
NAPT: Network Address and Port Translation NAPT: Network Address and Port Translation
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-device: Network Address Translator or Network Address and Port
Translator: An entity performing NAT or NAPT
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
3. Deployment Framework 3. Deployment Framework
3.1. Deployment Scenario 3.1. Deployment Scenario
Figure 1 shows a typical network deployment for Internet access. A Figure 1 shows a typical network deployment for Internet access. A
user's IPv4 host gains access to the Internet though a NAS, which user's IPv4 host gains access to the Internet though a NAS, which
facilitates the authentication of the endpoint and configures the facilitates the authentication of the endpoint and configures the
user's connection according to the authorization and configuration user's connection according to the authorization and configuration
data received from the AAA-server upon successful authentication. data received from the AAA-server upon successful authentication.
skipping to change at page 7, line 36 skipping to change at page 7, line 43
| 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 when a service provider Figure 2 depicts the deployment scenario when a service provider
introduces a NAT device to increase the efficiency of the global IPv4 introduces a NAT-device to increase the efficiency of the global IPv4
address pool utilization. The objective is to provide the customer address pool utilization. The objective is to provide the customer
with connectivity to the public IPv4 Internet. The NAT device with connectivity to the public IPv4 Internet. The NAT-device
performs network address and port (and optionally address family) performs network address and port (and optionally address family)
translation, depending on whether the access network uses private translation, depending on whether the access network uses private
IPv4 addresses or public IPv6 addresses, to public IPv4 addresses. IPv4 addresses or public IPv6 addresses, to public IPv4 addresses.
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
hampered. Provisioning static NAT bindings for particular endpoints, impacted. This includes cases like:
using different public IP address pools for different set of
endpoints; for example, residential or business customers, and o Provisioning static NAT bindings for particular endpoints
reporting allocated bindings on a per endpoint basis is burdensome
for a service provider if the NAT device is not aware of endpoints o Using different public IP address pools for different set of
and allows per endpoint control and management, which easily endpoints (for example, residential or business customers)
integrates with the already existing per endpoint management
infrastructure of the service provider. o Reporting allocated bindings on a per endpoint basis
o Integrate control of the NAT-device into the already existing per
endpoint management infrastructure of the service provider
+---------+ +---------+
| | | |
| AAA | | AAA |
| | | |
+---------+ +---------+
| |
| |
| |
| |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +--------+ +----------+
| IPv4/ | | | | | | IPv4 | | IPv4/ | | | | | | IPv4 |
| IPv6 |----| NAS |----| NAT |----| Internet | | IPv6 |----| NAS |----| NAT- |----| Internet |
| Host | | | | | | | | Host | | | | device | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +--------+ +----------+
<-------- Private IPv4 -----------><--- Public IPv4 ---> <-------- Private IPv4 ----------><--- Public IPv4 --->
<-------- Public IPv6 -----------><--- Public IPv4 ---> <-------- Public IPv6 ----------><--- Public IPv4 --->
Figure 2: Access network deployment with NAT Figure 2: Access network deployment with NAT
3.2. Diameter NAPT Control Application Overview 3.2. Diameter NAPT Control Application Overview
DNCA runs between a DNCA Agent on the NAT and DNCA Manager. DNCA DNCA runs between two DNCA Diameter peers. One DNCA Diameter peer
allows per endpoint control and management of NAT. Based on resides within the NAT-device, the other DNCA Diameter peer resides
Diameter, DNCA integrates well with the suite of Diameter within the NAT-Controller. DNCA allows per endpoint control and
applications deployed for per endpoint authentication, authorization, management of NAT within the NAT-device. Based on Diameter, DNCA
accounting, and policy control in service provider networks. integrates well with the suite of Diameter applications deployed for
per endpoint authentication, authorization, 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 Provides per endpoint reporting of the allocated NAT bindings.
o Provides unique identification of an endpoint on NAT device, AAA- o Provides unique identification of an endpoint on NAT-device, AAA-
server and NAS, to simplify correlation of accounting data server 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 either using accounting mechanisms or through an explicit
session query to the NAT. session query to the NAT.
3.3. Deployment Scenarios For DNCA 3.3. Deployment Scenarios For DNCA
The role of DNCA can be fulfilled by either the NAS or by an external DNCA can be deployed in different ways. Two common deployment
server, such as AAA-server. The two deployment scenarios are scenarios are outlined in Figure 3 ("integrated deployment") and
outlined in Figure 3 ("integrated deployment") and Figure 4 Figure 4 ("autonomous deployment"). The two scenarios differ in
("autonomous deployment"). which entity fulfills the role of the NAT-controller. Within the
figures (C) denotes the network element performing the role of the
Within the figures (M) denotes the network element, which takes on NAT-controller.
DNCA Manager role. Similarly, (A) identifies the network element,
which performs DNCA Agent role.
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 as much as device from external servers, such as the AAA-server. It is suited
possible. It is suited for environments where minimal changes to the for environments where minimal changes to the existing AAA deployment
existing AAA deployment are desired. As DNCA Manager the NAS, are desired. The NAS and the NAT-device are Diameter peers
initiates and manages session with the NAT device, exchanges NAT supporting the DNCA. The Diameter peer within the NAS, performing
specific configuration information and handles reporting and the role of the NAT-controller, initiates and manages sessions with
accounting information. The NAS receives reporting and accounting the NAT-device, exchanges NAT specific configuration information and
information from NAT device. With this information, the NAS provides handles reporting and accounting information. The NAS receives
a single accounting record for the user. This reduces the usage of reporting and accounting information from NAT-device. With this
an external accounting system for correlating the information information, the NAS can provide a single accounting record for the
received from multiple sources. endpoint. A system correlating the accounting information received
from 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,
NAS receives endpoint related authorization data from the AAA-server. the NAS receives endpoint related authorization data from the AAA-
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. NAS will initiate a DNCA session to the NAT and send the NAT-device. The NAS initiates a DNCA session to the NAT-device
the relevant authorization and configuration information for the and sends relevant authorization and configuration information for
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 or accounting requirements. The bindings allowed for the endpoint. The NAT-device sends its per
NAT device sends its per endpoint accounting information to the NAS, endpoint accounting information to the NAS, which aggregates the
which aggregates the accounting information received form the NAT accounting information received from the NAT-device with its local
device with its local accounting information for the endpoint into a accounting information for the endpoint into a single accounting
single accounting stream towards the AAA-server. stream towards the AAA-server.
+---------+ +---------+
| | | |
| AAA | | AAA |
| | | |
+---------+ +---------+
| |
| |
| |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +--------+ +----------+
| IPv4/ | | (M) | | (A) | | IPv4 | | IPv4/ | | (C) | | | | IPv4 |
| IPv6 |----| NAS |----| NAT |----| Internet | | IPv6 |----| NAS |----| NAT- |----| Internet |
| Host | | | | | | | | Host | | | | device | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +--------+ +----------+
<-------- Public IPv6 ----------><--- Public IPv4 ----> <-------- Public IPv6 ----------><--- Public IPv4 --->
<-------- Private IPv4 ----------><--- Public IPv4 ----> <-------- Private IPv4 ----------><--- Public IPv4 --->
Figure 3: NAT Control deployment: Integrated deployment Figure 3: NAT control deployment: Integrated deployment
The autonomous deployment approach decouples user management on NAS The autonomous deployment approach decouples user management on NAS
and NAT device. The AAA system performing the role of DNCA Manager and NAT-device. In the autonomous deployment approach, the AAA-
manages the connection to the NAT device, controls the per endpoint system and the NAT-device are the Diameter peers running the DNCA.
The AAA-system also serves as NAT-controller. It manages the
connection to the NAT-device, controls the per endpoint
configuration, and also receives accounting and reporting information configuration, and also receives accounting and reporting information
from the NAT device. Different from the integrated deployment from the NAT-device. Different from the integrated deployment
scenario, the autonomous deployment scenario does not "hide" the scenario, the autonomous deployment scenario does not "hide" the
existence of the NAT device from the AAA infrastructure. Here two existence of the NAT-device from the AAA infrastructure. Here two
accounting streams are received by the AAA-server for one particular accounting streams are received by the AAA-server for one particular
endpoint, one from the NAS, and one from the NAT device. endpoint, one from the NAS, and one from the NAT-device.
+---------+ +---------+
| (M) | | (C) |
| AAA |--------- | AAA |---------
| | | | | |
+---------+ | +---------+ |
| | | |
| | | |
| | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +---------+ +----------+
| IPv4/ | | | | (A) | | IPv4 | | IPv4/ | | | | | | IPv4 |
| IPv6 |----| NAS |----| NAT |----| Internet | | IPv6 |----| NAS |----| NAT- |----| Internet |
| Host | | | | | | | | Host | | | | device | | |
+--------+ +---------+ +---------+ +----------+ +--------+ +---------+ +---------+ +----------+
<-------- Public IPv6 ----------><---- Public IPv4 ---> <-------- Public IPv6 ----------><---- Public IPv4 --->
<-------- Private IPv4 ----------><---- Public IPv4 ---> <-------- Private IPv4 ----------><---- Public IPv4 --->
Figure 4: NAT Control deployment: Autonomous deployment Figure 4: NAT control deployment: Autonomous deployment
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 this section forward references some of the commands and
AVPs defined for DNCA. Please refer to Section 6 and Section 8 for AVPs defined for DNCA. Please refer to Section 6 and Section 8 for
details. details. DNCA runs between a Diameter peer residing in a NAT-
controller and a Diameter peer residing in a NAT-device. The
4.1. Parties Involved Diameter peer within the NAT-controller is always the control
requesting entity: It initiates, updates, or terminates the sessions.
Authorization and control models supported by this application Sessions are initiated when the NAT-controller learns about a new
include the following parties: endpoint (i.e., host) that requires a NAT service. This could for
example be due to the entity hosting the NAT-controller receiving
o DNCA Agent: DNCA Agent is part of the NAT device authentication, authorization, or accounting requests for or from the
endpoint. Alternate methods that could trigger session set up
o DNCA Manager include local configuration, receipt of a packet from a formerly
unknown IP-address, etc.
The NAT control requesting entity is always DNCA Manager. DNCA
Manager always initiates, updates, or terminates the sessions. This
mode of operation is sometimes also referred to as "push mode".
DNCA Manager can be NAS or AAA-server. DNCA Manager initiates a
session with DNCA Agent when it learns about the subscriber. DNCA
Manager may learn about a subscriber when it receives authentication,
authorization, or accounting request for that subscriber or by some
other means, such as on the box configuration to identify a
subscriber with respect to his IP packets.
4.2. Session Establishment 4.1. Session Establishment
DNCA Manager establishes a session with DNCA Agent to control the The DNCA Diameter peer within the NAT-controller establishes a
behavior of the NAT device. During session establishment, DNCA session with the DNCA Diameter peer within the NAT-device to control
Manager passes along configuration information to DNCA Agent. The the behavior of the NAT function within the NAT-device. During
session configuration information comprises the maximum number of session establishment, the DNCA Diameter peer within the NAT-
bindings allowed for the endpoint associated with this session, a set controller passes along configuration information to DNCA Diameter
of pre-defined NAT bindings to be established for this endpoint, or a peer within the NAT-device. The session configuration information
description of the address pool, external addresses to be allocated comprises the maximum number of bindings allowed for the endpoint
from. associated with this session, a set of pre-defined NAT bindings to be
established for this endpoint, or a description of the address pool,
that external addresses are to be allocated from.
DNCA Manager initiates the Diameter NAT Control session to DNCA The DNCA Diameter peer within the NAT-controller generates a NAT-
Agent. DNCA Manager generates a NAT-Control Request (NCR) message to Control Request (NCR) message to the DNCA Diameter peer within the
DNCA Agent with NC-Request-Type AVP set to INITIAL_REQUEST. On NAT-device with NC-Request-Type AVP set to INITIAL_REQUEST to
receipt of NCR DNCA Agent sets up a new session for the endpoint initiate a Diameter NAT control session. On receipt of a NCR the
associated with the endpoint classifier(s) contained in the NCR. DNCA Diameter peer within the NAT-device sets up a new session for
DNCA Agent notifies DNCA Manager about successful session setup using the endpoint associated with the endpoint classifier(s) contained in
a NAT-Control Answer (NCA) message with Result-Code set to the NCR. The DNCA Diameter peer within the NAT-device notifies its
DIAMETER_SUCCESS. Figure 5 shows the initial protocol interaction DNCA Diameter peer within the NAT-controller about successful session
between DNCA Manager and DNCA Agent. setup using a NAT-Control Answer (NCA) message with Result-Code set
to DIAMETER_SUCCESS. Figure 5 shows the initial protocol 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, which may be included, the session. The configuration information which 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 a subscriber requires a fixed session; for example, in case a user requires a fixed external IP-
external IP- address/port pair for one of the applications. address/port pair for one of his applications.
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 address pool(s) to be used for the o A description of the external IP-address pool(s) to be used for
session. the session.
o A reference to a predefined binding rule on DNCA Agent, which is o A reference to a predefined binding rule on the NAT-device, which
applied to the session. Such a predefined binding rule on DNCA is applied to the session. Such a predefined binding rule on the
Agent may contain, for example, the name of the IP address pool NAT-device may contain, for example, the name of the IP-address
that external IP addresses should be allocated from, maximum pool that external IP-addresses should be allocated from, the
number of bindings permitted for the endpoint etc. maximum number of bindings permitted for the endpoint, etc.
In certain cases, DNCA Agent 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 Agent receives a NCR from a DNCA Manager with NC- o If a DNCA Diameter peer within the NAT-device receives a NCR from
Request-Type AVP set to INITIAL_REQUEST that identifies an already a DNCA Diameter peer within a NAT-controller with NC- Request-Type
existing session; that is, DNCA Manager and endpoint identifier AVP set to INITIAL_REQUEST that identifies an already existing
match an already existing session, DNCA Agent returns NCA with session; that is, DNCA Diameter peer and endpoint identifier match
Result-Code set to SESSION_EXISTS, and provides the Session-Id of an already existing session, the DNCA Diameter peer within the
the existing session in Duplicate-Session-Id AVP. NAT-device returns NCA with Result-Code set to SESSION_EXISTS, and
provides the Session-Id of the existing session in the Duplicate-
Session-Id AVP.
o If a DNCA Agent receives an NCR from a DNCA Manager with NC- o If a DNCA Diameter peer within the NAT-device receives a NCR from
Request-Type AVP set to INITIAL_REQUEST that matches more than one a DNCA Diameter peer within a NAT-controller with NC- Request-Type
of the already existing sessions; that is, DNCA Manager and AVP set to INITIAL_REQUEST that matches more than one of the
endpoint identifier match already existing sessions, DNCA Agent already existing sessions; that is, DNCA Diameter peer and
returns a NCA with Result-Code set to INSUFFICIENT-CLASSIFIERS. endpoint identifier match already existing sessions, the DNCA
In case a DNCA Manager receives NCA that reports Insufficient- Diameter peer within the NAT-device returns a NCA with Result-Code
Classifiers, it may choose to retry establishing a new session set to INSUFFICIENT-CLASSIFIERS. In case a DNCA Diameter peer
using additional and more specific classifiers. receives a NCA that reports Insufficient-Classifiers, it may
choose to retry establishing a new session using additional or
more specific classifiers.
o If the NCR contains a binding rule not defined on the NAT device, o If the NCR contains a binding rule not defined on the NAT-device,
DNCA Agent returns NCA with Result-Code AVP set to the DNCA Diameter peer within the NAT-device returns NCA with
UNKNOWN_BINDING_RULE. Result-Code AVP set to UNKNOWN_BINDING_RULE.
o In case DNCA Agent 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, it will return a NCA with Result-Code set to requested in the NCR, the DNCA Diameter peer will return a NCA
BINDING_FAILURE. DNCA Agent, that is NAT device, treats a NCR as with Result-Code set to BINDING_FAILURE. A DNCA Diameter peer
an atomic operation; hence none of the requested bindings will be within a NAT-device treats a NCR as an atomic operation; hence
established by the NAT device. Either all requested actions none of the requested bindings will be established by the NAT-
within a NCR are completed successfully, or the entire request device. Either all requested actions within a NCR are completed
fails. successfully, or the entire request fails.
o If DNCA Agent does not have sufficient resources to process a o If a NAT-device does not have sufficient resources to process a
request, it returns NCA with Result-Code set to RESOURCE_FAILURE. request, the DNCA Diameter peer returns a NCA with Result-Code set
to RESOURCE_FAILURE.
o In case Max-NAT-Binding and NAT-Control-Definition are included in o In case Max-NAT-Binding and NAT-Control-Definition are included in
the NCR along with a reference to a binding rule; that is, a the NCR along with a reference to a binding rule; that is, a
predefined template on NAT device, and the values in Max-NAT- predefined template on NAT-device, and the values in Max-NAT-
Binding and NAT-Control-Definition contradict those specified in Binding and NAT-Control-Definition contradict those specified in
the pre-defined binding rule, Max-NAT-Binding and NAT-Control- the pre-defined binding rule, Max-NAT-Binding and NAT-Control-
Definition override the values specified in the binding rule. Definition override the values specified in the binding rule.
DNCA Manager DNCA Agent NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer)
| | | |
| | | |
| | | |
Trigger | Trigger |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| (INITIAL_REQUEST, endpoint classifier, | | (INITIAL_REQUEST, endpoint classifier, |
| session id, NAT control config data) | | session id, NAT control config data) |
| | | |
| | | |
| Create session state | |
| |
| If Able to comply
| with Request then
| Create session state
| | | |
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| (result code) | | (result code) |
| | | |
| | | |
Figure 5: Initial NAT Control request and session establishment Figure 5: Initial NAT control request and session establishment
4.3. Session Re-Authorization 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
reply with a NCA with Result-Code set to DIAMETER_SUCCESS.
Session re-authorization is performed if DNCA Manager desires to 4.2. Session Re-Authorization
change the behavior of the NAT for an existing session. Re-
authorization could be used, for example, to change the number of
allowed bindings for a particular session, or establish or remove a
pre-defined binding.
DNCA Manager generates a NCR message to DNCA Agent with NC-Request- Session re-authorization is performed if the NAT-controller desires
Type AVP set to UPDATE_REQUEST upon receiving a trigger signal. In to change the behavior of the NAT-device for an existing session.
case the session is updated successfully, DNCA Agent notifies DNCA Session re-authorization could be used, for example, to change the
Manager about successful session update using a NAT-Control Answer number of allowed bindings for a particular session, or establish or
(NCA) message with Result-Code set to DIAMETER_SUCCESS. Figure 6 remove a pre-defined binding.
shows the protocol interaction between DNCA Manager and DNCA Agent.
In certain cases, DNCA Agent may not be able to perform the tasks The DNCA Diameter peer within the NAT-controller generates a NCR
message to DNCA Diameter peer within NAT-device with NC-Request-Type
AVP set to UPDATE_REQUEST upon receiving a trigger signal. If the
session is updated successfully, the DNCA Diameter peer within the
NAT-device notifies the DNCA Diameter peer within the NAT-controller
about the successful session update using a NAT-Control Answer (NCA)
message with Result-Code set to DIAMETER_SUCCESS. Figure 6 shows the
protocol interaction between the two DNCA Diameter peers.
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 Agent receives a NCR update or query request for a non- o If DNCA Diameter peer within a NAT-device receives a NCR update or
existent session, it sets Result-Code in the answer to query request for a non-existent session, it sets Result-Code in
DIAMETER_UNKNOWN_SESSION_ID. the answer to DIAMETER_UNKNOWN_SESSION_ID.
o If the NCR contains a binding rule not defined on the NAT device, o If the NCR contains a binding rule not defined on the NAT-device,
DNCA Agent returns NCA with Result-Code AVP set to a NCA with Result-Code AVP set to UNKNOWN_BINDING_RULE is
UNKNOWN_BINDING_RULE. returned.
o If DNCA Agent cannot establish the requested binding because the o If the NAT-device cannot establish the requested binding because
maximum number of allowed bindings has been reached for the the maximum number of allowed bindings has been reached for the
Endpoint Classifier, it returns NCA with Result-Code AVP set to endpoint classifier, a NCA with Result-Code AVP set to
MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT. MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT by the DNCA Diameter peer.
o If DNCA Agent cannot establish some or all of the bindings o If the NAT-device cannot establish some or all of the bindings
requested in a NCR, but has not yet reached the maximum number of requested in a NCR, but has not yet reached the maximum number of
allowed bindings for the subscriber, it returns a NCA with Result- allowed bindings for the endpoint, a NCA with Result-Code set to
Code set to BINDING_FAILURE. DNCA Agent (i.e., NAT device) treats BINDING_FAILURE is returned. As already noted, the DNCA Diameter
a NCR as an atomic operation. Hence none of the requested peer in a NAT-device treats a NCR as an atomic operation. Hence
bindings will be established by NAT device. Either all requested none of the requested bindings will be established by the NAT-
actions within a NCR are either successful or failed completely. device in case of failure. Actions requested within a NCR are
either all successful or all fail.
o If DNCA Agent does not have sufficient resources to process a o If the NAT-device does not have sufficient resources to process a
request, it returns NCA with Result-Code set to RESOURCE_FAILURE. request, a NCA with Result-Code set to RESOURCE_FAILURE is
returned.
o If a NCR redefines the maximum number of NAT bindings allowed for o If a NCR redefines the maximum number of NAT-bindings allowed for
the endpoint, the new value will override any previously defined the endpoint, the new value will override any previously defined
limit on NAT bindings. It depends on the implementation of the limit on NAT bindings. It depends on the implementation of the
NAT device on how the NAT device copes with a case where the new NAT-device on how the NAT-device copes with a case where the new
value is lower than the actual number of allocated bindings. value is lower than the actual number of allocated bindings.
Typically the NAT device refrains from enforcing the new limit Typically the NAT-device refrains from enforcing the new limit
immediately; that is, actively remove bindings, but rather immediately; that is, actively remove bindings, but rather
disallow the establishment of new bindings until the current disallow the establishment of new bindings until the current
number of bindings is lower than the newly established maximum number of bindings is lower than the newly established maximum
number of allowed bindings. number of allowed bindings.
o If a NCR specifies a new binding rule, predefined on DNCA Agent, o If a NCR specifies a new binding rule, predefined on the NAT-
the binding rule overrides any previously defined rules for the device, the binding rule overrides any previously defined rule for
session. the session.
o If Max-NAT-Binding and NAT-Control-Definition AVPs are included in o If Max-NAT-Binding and NAT-Control-Definition AVPs are included in
the NCR along with a reference to a binding rule (a predefined the NCR along with a reference to a binding rule (a predefined
template on NAT device) and the values in Max-NAT-Binding and NAT- template on the NAT-device) and the values in Max-NAT-Binding and
Control-Definition AVPs contradict those specified in the pre- NAT-Control-Definition AVPs contradict those specified in the pre-
defined binding rule, Max-NAT-Binding and NAT-Control-Definition defined binding rule, Max-NAT-Binding and NAT-Control-Definition
AVPs override the values specified in the binding rule. AVPs override the values specified in the binding rule.
Note: Already established bindings for the session will not be Note: Already established bindings for the session will not be
affected. affected in case the tasks requested within the NCR cannot be
DNCA Manager DNCA Agent completed.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer)
| | | |
| | | |
| | | |
Change of session | Change of session |
attributes | attributes |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| (UPDATE_REQUEST session id, | | (UPDATE_REQUEST session id, |
| NAT control config data) | | NAT control config data) |
| | | |
| | | |
| If able to comply
| with the request:
| Update session state | Update session state
| | | |
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| (result code) | | (result code) |
| | | |
| | | |
Figure 6: NAT Control request for session update Figure 6: NAT control request for session update
4.4. Session and Binding Query 4.3. Session and Binding Query
Session query can be used by DNCA Manager to either retrieve Session query can be used by the DNCA Diameter peer within the NAT-
information on the current bindings for a particular session at the controller to either retrieve information on the current bindings for
NAT device or discover the session identifier for a particular a particular session at the NAT-device or discover the session
external IP address/port pair. identifier for a particular external IP address/port pair.
DNCA Manager initiates a session query by sending a NCR message to A DNCA Diameter peer within the NAT-controller starts a session query
DNCA Agent with NC-Request-Type AVP set to QUERY_REQUEST. Figure 7 by sending a NCR message with NC-Request-Type AVP set to
shows the protocol interaction between DNCA Manager and DNCA Agent. QUERY_REQUEST. Figure 7 shows the protocol interaction between the
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
DNCA Manager retrieve the current set of bindings for a specific the DNCA Diameter peer within the NAT-controller to retrieve the
session. The second type of query request is used to retrieve the current set of bindings for a specific session. The second type of
session identifiers, along with the associated bindings, matching a query request is used to retrieve the session identifiers, along with
criteria. This enables DNCA Manager to find the sessions, which the associated bindings, matching a criteria. This enables the DNCA
utilize a specific external IP address. Diameter peer within the NAT-controller to find those sessions, which
utilize a specific external 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: DNCA Agent on receiving NCR, looks up session particular session: On receiving a NCR, the NAT-device looks up
information for the session ID contained in the NCR, and reports the session information for the session ID contained in the NCR,
all currently active NAT bindings for the session using NCA and reports all currently active NAT-bindings for the session
message with Result-Code set to DIAMETER_SUCCESS. In this case using a NCA message with Result-Code set to DIAMETER_SUCCESS. In
the NCR MUST NOT contain a NAT-Control-Definition AVP. Each NAT this case the NCR MUST NOT contain a NAT-Control-Definition AVP.
binding is reported in a NAT-Control-Definition AVP. In case the Each NAT-binding is reported in a NAT-Control-Definition AVP. In
session ID is unknown, DNCA Agent returns NCA with Result-Code case the session ID is unknown, the DNCA Diameter peer within the
set to DIAMETER_UNKNOWN_SESSION_ID. NAT-device returns NCA with Result-Code set to
DIAMETER_UNKNOWN_SESSION_ID.
2. Retrieve session IDs and internal IP address/port pairs for one 2. Retrieve session IDs and internal IP address/port pairs for one
or multiple external IP address/port pairs: If DNCA Manager or multiple external IP-address/port pairs: If the DNCA Diameter
wishes to retrieve the session ID(s) for one or multiple external peer within the NAT-controller wishes to retrieve the session
IP address/port pairs, it MUST include the external IP address/ ID(s) for one or multiple external IP-address/port pairs, it MUST
port pair(s) as part of the NAT-Control-Definition AVP of the include the external IP-address/port pair(s) as part of the NAT-
NCR. The session ID is not included in the NCR or the NCA for Control-Definition AVP of the NCR. The session ID is not
this type of a query. DNCA Agent reports the NAT bindings and included in the NCR or the NCA for this type of a query. The
associated session IDs corresponding to the external IP address/ DNCA Diameter peer within the NAT-device reports the NAT-bindings
port pairs in a NCA message with Result-Code set to and associated session IDs corresponding to the external IP-
DIAMETER_SUCCESS with the same session ID, which is used in NCR. address/port pairs in a NCA message with Result-Code set to
In case an external IP address/port pair has no associated DIAMETER_SUCCESS with the same session ID, which was used in NCR.
existing NAT binding, the NAT-Control-Definition AVP contained in In case an external IP-address/port pair has no associated
existing NAT-binding, the NAT-Control-Definition AVP contained in
the reply just contains the NAT-External-Address AVP. the reply just contains the NAT-External-Address AVP.
DNCA Manager DNCA Agent NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer)
| | | |
| | | |
| | | |
DNCA Session Established | DNCA Session Established |
| | | |
| NCR | | NCR |
|------------------------------------------>| |------------------------------------------>|
| (QUERY_REQUEST) | | (QUERY_REQUEST) |
| | | |
| | | |
| | | |
| Look up corresponding session | Look up corresponding session
| and associated NAT Bindings | and associated NAT-bindings
| | | |
| NCA | | NCA |
|<------------------------------------------| |<------------------------------------------|
| (Result-Code) | | (Result-Code) |
| | | |
| | | |
Figure 7: Session Query Figure 7: Session query
4.5. Session Termination 4.4. Session Termination
DNCA Manager generates a Session Terminate Request (STR) message to Similar to session initiation, session tear down is always initiated
DNCA Agent upon receiving a trigger signal. The source of the by the DNCA Diameter peer within the NAT-controller. The DNCA
trigger signal is outside the scope of this document. DNCA Agent Diameter peer sends a Session Terminate Request (STR) message to its
sends accounting stop record reporting all the bindings and notifies peer within the NAT-device upon receiving a trigger signal. The
DNCA Manager about successful session termination using a Session source of the trigger signal is outside the scope of this document.
In response, the DNCA Diameter peer within the NAT-device sends an
accounting stop record reporting all bindings and notifies its DNCA
Diameter peer about successful session termination using a Session
Terminate Answer (STA) message with Result-Code set to Terminate Answer (STA) message with Result-Code set to
DIAMETER_SUCCESS. Figure 8 shows the protocol interaction between DIAMETER_SUCCESS. Figure 8 shows the protocol interaction between
DNCA Manager and DNCA Agent. the two DNCA Diameter peers.
If a DNCA Agent receives STR from a DNCA Manager and fails to find a If a DNCA Diameter peer within a NAT-device receives a STR and fails
matching session, DNCA Agent returns STA with Result-Code set to to find a matching session, the DNCA Diameter peer returns a STA with
DIAMETER_UNKNOWN_SESSION_ID. Result-Code set to DIAMETER_UNKNOWN_SESSION_ID.
DNCA Manager DNCA Agent NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer)
| | | |
| | | |
Trigger | Trigger |
| | | |
| STR | | STR |
|------------------------------------------->| |------------------------------------------->|
| (session id) | | (session id) |
| | | |
| | | |
| Remove NAT bindings | Remove NAT-bindings
| of session | of session
| | | |
| | | |
| Send accounting stop | | Send accounting stop |
|<-------------------------------------------| |<-------------------------------------------|
| for all session bindings | | reporting all session bindings |
| | | |
| Terminate Session / | Terminate session /
| Remove session state | Remove session state
| | | |
| | | |
| | | |
| STA | | STA |
|<-------------------------------------------| |<-------------------------------------------|
| (Result-Code) | | (Result-Code) |
| | | |
Figure 8: Terminate NAT Control session Figure 8: Terminate NAT control session
4.6. DNCA Manager and Agent Failures 4.5. Session Abort
This document does not cover details in case DNCA Manager and DNCA An Abort-Session-Request (ASR) message is sent from the DNCA Diameter
Agent are out of sync. This happens when DNCA Manager or DNCA Agent peer within the NAT-device to the DNCA Diameter peer within the NAT-
restart, (temporary) loss of network connectivity etc. DNCA Manager controller when it is unable to maintain a session due to resource
and DNCA Agent MUST have builtin redundancy support to recover state limitations. The DNCA Diameter peer within the NAT-controller
in case of failure. acknowledges successful session abort using a Abort Session Answer
(ASA) message with Result-Code set to DIAMETER_SUCCESS. Figure 9
shows the protocol interaction between the DNCA Diameter peers. The
DNCA Diameter peers will start a session termination procedure as
described in Section 4.4 following an ASA with Result-Code set to
DIAMETER_SUCCESS.
If the DNCA Diameter peer within a NAT-controller receives an ASR but
fails to find a matching session, it returns an ASA with Result-Code
set to DIAMETER_UNKNOWN_SESSION_ID. If the DNCA Diameter peer within
the NAT-controller is unable to comply with the ASR for any other
reason, an ASA with Result-Code set to DIAMETER_UNABLE_TO_COMPLY is
returned.
NAT-controller (DNCA Diameter peer) NAT-device (DNCA Diameter peer)
| |
| |
| Trigger
| |
| ASR |
|<-------------------------------------------|
| (session id) |
| |
| |
| ASA |
|------------------------------------------->|
| (Result-Code) |
| |
| |
| On successful ASA |
|<------Session Termination Procedure------->|
Figure 9: Abort NAT control session
4.6. Failure cases of the DNCA Diameter peers
This document does not specify the behavior in case NAT-device and
NAT-controller, or their respective DNCA Diameter peers are out of
sync. This could happen for example if one of the entities restarts,
in case of a (temporary) loss of network connectivity etc. The
peering entities MUST have built-in redundancy support to recover
state in case of failure.
Example failure cases include the following: Example failure cases include the following:
o DNCA Manager loses session state (e.g. due to a restart). In this o NAT-controller and the DNCA Diameter peer within the NAT-
case, controller lose state (e.g. due to a restart). In this case,
* DNCA Agent may receive a NCR with NC-Request-Type AVP set to * the DNCA Diameter peer within the NAT-device may receive a NCR
INITIAL_REQUEST that matches an existing session of DNCA Agent. with NC-Request-Type AVP set to INITIAL_REQUEST that matches an
DNCA Agent returns a Result-Code that contains Duplicate- existing session of the DNCA Diameter peer within the NAT-
Session-Id AVP to report the Session-ID of existing session. device. The DNCA Diameter peer within the NAT-device returns a
DNCA Manager may send an explicit Sesstion Terminate Request Result-Code that contains Duplicate-Session-Id AVP to report
(STR) for the older session, which was lost. the Session-ID of the existing session. The DNCA Diameter peer
within the NAT-controller may send an explicit Session
Terminate Request (STR) for the older session, which was lost.
* DNCA Manager may receive accounting records for a session that * a DNCA Diameter peer may receive accounting records for a
does not exist. DNCA Manager sends an accounting answer with session that does not exist. The DNCA Diameter peer sends an
Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. On receiving accounting answer with Result-Code set to
this, DNCA Agent clears the session and removes the associated DIAMETER_UNKNOWN_SESSION_ID in response. On receiving the
session state. response, the DNCA Diameter peer clears the session and removes
the associated session state.
o DNCA Agent loses session state. In such a case, DNCA Agent may o NAT-device and the DNCA Diameter peer within NAT-device lose
receive a NCR with NC-Request-Type AVP set to UPDATE_REQUEST for a state. In such a case, the DNCA Diameter peer may receive a NCR
non-existent session. DNCA Agent returns NCA with Result-Code set with NC-Request-Type AVP set to UPDATE_REQUEST for a non-existent
session. The DNCA Diameter peer returns NCA with Result-Code set
to DIAMETER_UNKNOWN_SESSION_ID. to DIAMETER_UNKNOWN_SESSION_ID.
o DNCA Manager is unreachable, for example detected by Diameter o The DNCA Diameter peer within the NAT-controller is unreachable,
watchdog, or down and accounting request from DNCA Agent fails to for example detected by Diameter watchdog, or down and accounting
get a response. The mechanism to ensure that a DNCA Manager no requests from the DNCA Diameter peer fail to get a response. The
longer has associated state for a session being cleared by a DNCA mechanism to ensure that a DNCA Diameter peer within the NAT-
Agent is beyond the scope of this document. controller no longer has associated state for a session which was
cleared or removed by the DNCA Diameter peer within the NAT-device
is beyond the scope of this document.
o DNCA Agent is unreachable or down and NCR requests fail to get a o The DNCA Diameter peer within the NAT-device is unreachable or
response. Handling of this case depends on the actual service down and NCR requests fail to get a response. Handling of this
offering of the service provider. The service provider can choose case depends on the actual service offering of the service
to terminate the access session to the endpoint. provider. The service provider could for example choose to stop
offering connectivity service.
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 defined by [RFC3588] applies with the
clarifications listed in the present specification. clarifications listed in the present specification.
5.1. Securing Diameter Messages 5.1. Securing Diameter Messages
For secure transport of Diameter messages recommendations in For secure transport of Diameter messages recommendations in
[RFC3588] apply. [RFC3588] apply.
DNCA Agent MAY verify the identity of DNCA Manager during the DNCA Diameter peers MAY verify their identity during the Capabilities
Capabilities Exchange Request procedure. Exchange Request procedure.
DNCA Agent MAY verify if DNCA Manager that issues a NCR command is A DNCA Diameter peer within the NAT-device MAY verify that a DNCA
allowed and it is based on: Diameter peer that issues a NCR command is allowed to do so based on:
o The identity of DNCA Manager 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 (accounting session state machine, related
command codes and AVPs) is defined in Section 9 below. command codes and AVPs) is defined in Section 9 below.
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
skipping to change at page 19, line 34 skipping to change at page 22, line 16
5.2. Accounting Functionality 5.2. Accounting Functionality
Accounting functionality (accounting session state machine, related Accounting functionality (accounting session state machine, related
command codes and AVPs) is defined in Section 9 below. command codes and AVPs) is defined in Section 9 below.
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 [RFC3588], which MUST NOT be changed during the lifetime of a DNCA
session. The Diameter Session-ID serves as the global endpoint session. The Diameter Session-ID serves as the global endpoint
identifier. DNCA Agent and DNCA Manager maintain state associated identifier. The DNCA Diameter peers maintain state associated with
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. DNCA session MUST updating, accounting, and terminating the session. DNCA session MUST
NOT have more than one outstanding request at any given instant. NOT have more than one outstanding request at any given instant. A
DNCA Agent sends an Abort-Session-Request as defined in [RFC3588] if DNCA Diameter peer sends an Abort-Session-Request as defined in
it is unable to maintain sessions due to resource limitation. [RFC3588] if it is unable to maintain sessions due to resource
limitation.
5.4. Routing Considerations 5.4. Routing Considerations
It is assumed that DNCA Manager knows the DiameterIdentity of DNCA It is assumed that the DNCA Diameter peer within a NAT-controller
Agent for a given endpoint. Both the Destination-Realm and knows the DiameterIdentity of the Diameter peer within a NAT-device
Destination-Host AVPs are present in the request from DNCA Manager to for a given endpoint. Both the Destination-Realm and Destination-
DNCA Agent. 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.
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 in the Auth- support for DNCA by including the value of TBD 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 command[RFC3588].
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 NAT-
bindings. 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 and the "R" bit set in the Command Flags field, is sent set to TBD and the "R" bit set in the Command Flags field, is sent
from DNCA Manager to DNCA Agent in order to install NAT bindings. from the DNCA Diameter peer within the NAT-controller to the DNCA
Diameter peer within the NAT-device in order to install NAT-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, Calling-Station-ID AVPs serve as identifiers for the
subscriber. endpoint.
Message Format: Message format:
< NC-Request > ::= < Diameter Header: TBD, REQ, PXY> < NC-Request > ::= < Diameter Header: TBD, REQ, PXY>
[ Session-Id ] [ Session-Id ]
{ 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 }
[ Origin-State-Id ] [ Origin-State-Id ]
*1 [ NAT-Control-Remove ] *1 [ NAT-Control-Remove ]
skipping to change at page 21, line 9 skipping to change at page 23, line 40
[ 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 and the "R" bit cleared in the Command Flags field, field set to TBD and the "R" bit cleared in the Command Flags field,
is sent by DNCA Agent in response to NAT-Control-Request command. is sent by the DNCA Diameter peer within the NAT-device in response
to NAT-Control-Request command.
Message format:
Message Format:
<NC-Answer> ::= < Diameter Header: TBD, PXY > <NC-Answer> ::= < Diameter Header: TBD, PXY >
[ Session-Id ] [ Session-Id ]
{ Origin-Host } { Origin-Host }
{ Origin-Realm } { Origin-Realm }
{ NC-Request-Type } { Result-Code }
[ Result-Code ] [ 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 ]
* [ 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 DNCA session, which MUST be observed by all the life cycle of DNCA session, which MUST be observed by all
implementations of DNCA Diameter application. DNCA Agent and Manager implementations of the DNCA Diameter application. The DNCA Diameter
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 [RFC3588]. 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 as 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 DNCA In the state table, the event 'Failure to send NCR' means that the
Manager is unable to send command NCR to the desired destination. DNCA Diameter peer within the NAT-controller is unable to send the
This could be due to the peer being down, or due to the peer sending NCR command to the desired destination. This could be due to the
back a transient failure or temporary protocol error notification peer being down, or due to the peer sending back the transient
DIAMETER_TOO_BUSY or DIAMETER_LOOP_DETECTED in the Result-Code AVP of failure or temporary protocol error notification DIAMETER_TOO_BUSY or
NCA. DIAMETER_LOOP_DETECTED in the Result-Code AVP of NCA.
In the state table "FAILED NCA" means that DNCA Agent was not able to In the state table "FAILED NCA" means that the DNCA Diameter peer
honor corresponding NCR. This can happen due to any of the transient within the NAT-device was not able to honor the corresponding NCR.
and permanent error at DNCA Agent indicated by the following error This can happen due to any transient and permanent error at the NAT-
Result-Code values - RESOURCE_FAILURE, UNKNOWN_BINDING_RULE_NAME, device or its associated DNCA Diameter peer within indicated by the
BINDING_FAILURE, MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT, following error Result-Code values: RESOURCE_FAILURE,
SESSION_EXISTS, INSUFFICIENT_CLASSIFIERS UNKNOWN_BINDING_RULE_NAME, BINDING_FAILURE,
MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT, SESSION_EXISTS,
INSUFFICIENT_CLASSIFIERS.
The following state machine is observed by a DNCA Manager: The following state machine is observed by a DNCA Diameter peer
MANAGER within a NAT-controller. The state machine description uses the term
"access session" to describe the connectivity service offered to the
endpoint or host. "Access session" should not be confused with the
Diameter session ID.
DNCA Diameter peer within a NAT-controller
State Event Action New State State Event Action New State
------------------------------------------------------------- -------------------------------------------------------------
Idle New Host 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 Sent STR Discon Pending Successful NCA Sent STR Discon
received received
but Agent unable to provide but peer unable to provide
service service
Pending Error processing successful Sent STR Discon Pending Error processing successful Sent STR Discon
NCA NCA
Pending Failed Cleanup Idle Pending Failed Cleanup 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 Cleanup Idle Open Failed Cleanup 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
client will comply with with access session will be with
request to end the session Result-Code terminated Result-Code
= SUCCESS, = SUCCESS,
Send STR. Send STR.
Open ASR Received, Send ASA Open Open ASR Received, Send ASA Open
client will not comply with with access session will not with
request to end the session 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
user/device user/device
The following state machine is observed by a DNCA Agent: The following state machine is observed by a DNCA Diameter peer
within a NAT-device.
AGENT DNCA Diameter peer within a NAT-device
State Event Action New State State Event Action New State
------------------------------------------------------------- -------------------------------------------------------------
Idle NCR request Send Open Idle 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
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 Cleanup NAT control service Cleanup
Open Unable to continue Send ASR Discon Open Unable to continue Send ASR Discon
providing requested providing requested
NAT control service NAT control service
Discon Failure to send ASR Wait, Discon Discon Failure to send ASR Wait, Discon
resend ASR resend ASR
Discon ASR successfully sent and Cleanup Idle Discon ASR successfully sent and Cleanup 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
Cleanup. Cleanup.
8. DNCA AVPs 8. DNCA AVPs
8.1. Reused Base Protocol AVPs 8.1. Reused Base Protocol AVPs
AVPs reused from Diameter Base Protocol [RFC3588] are listed below. AVPs reused from Diameter Base Protocol [RFC3588] are listed below.
skipping to change at page 25, line 33 skipping to change at page 28, line 33
|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 |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|M - Mandatory bit. An AVP with "M" bit set and its value MUST be | |M - Mandatory bit. An AVP with "M" bit set and its value MUST be |
| supported and recognized by a Diameter entity in order the | | supported and recognized by a Diameter entity in order the |
| message, which carries this AVP, to be accepted. | | message, which carries this AVP, to be accepted. |
|P - Indicates the need for encryption for end-to-end security. | |P - Indicates the need for encryption for end-to-end security. |
+-------------------------------------------------------------------+ +-------------------------------------------------------------------+
Figure 9: DIAMETER AVPs used from Diameter base Figure 10: DIAMETER AVPs used from Diameter base
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. Diameter NAT Control Application is TBD.
8.2. Additional Result-Code AVP Values 8.2. Additional Result-Code AVP Values
This section defines new values for the Result-Code AVP which SHALL This section defines new values for the Result-Code AVP which SHALL
be supported by all Diameter implementations that conform to the be supported by all Diameter implementations that conform to the
present document. present document.
skipping to change at page 26, line 11 skipping to change at page 29, line 11
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) RESOURCE_FAILURE (TBD)
DNCA Agent indicates that the binding could not be installed or The DNCA Diameter peer within the NAT-device indicates that the
a new session could not be created due to resource shortage. binding could not be installed or a new session could not be
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_RULE_NAME (TBD) UNKNOWN_BINDING_RULE_NAME (TBD)
DNCA Agent indicates that the binding could not be installed or The DNCA Diameter peer within the NAT-device indicates that the
a new session could not be created due to resource shortage. binding could not be installed or a new session could not be
created because the specified NAT-Control-Binding-Rule AVP,
that refers to a predefined policy template in the NAT-device,
is unknown.
BINDING_FAILURE (TBD) BINDING_FAILURE (TBD)
DNCA indicates that the requested binding(s) could not be DNCA indicates that the requested binding(s) could not be
installed. installed. For example: Requested ports are already in use.
MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT (TBD) MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT (TBD)
DNCA Agent denies the request because the maximum number of The DNCA Diameter peer within the NAT-device denies the request
allowed bindings has been reached for the specified Endpoint because the maximum number of allowed bindings has been reached
Classifier. for the specified endpoint classifier.
SESSION_EXISTS (TBD) SESSION_EXISTS (TBD)
DNCA Agent denies request to initialize a new session, if it The DNCA Diameter peer within the NAT-device denies request to
already has a DNCA session that uses the same set of initialize a new session, if it already has a DNCA session that
classifiers as indicated by DNCA Manager in the new session 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) INSUFFICIENT_CLASSIFIERS (TBD)
DNCA Agent defines request to initialize a new session, if the The DNCA Diameter peer within the NAT-device requests to
classifiers in the request match more than one of the existing initialize a new session, if the classifiers in the request
sessions on DNCA Agent. match more than one of the existing sessions on the DNCA
Diameter peer within the NAT-device.
8.3. Reused NASREQ Diameter Application AVPs 8.3. Reused NASREQ Diameter Application AVPs
The following AVPs are reused from Diameter Network Access Server The following AVPs are reused from Diameter Network Access Server
Application [RFC4005]. Application [RFC4005].
+---------------------+ +---------------------+
| 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 | | | | | | | |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
Figure 10: Reused NASREQ Diameter application AVPs Figure 11: Reused NASREQ Diameter application AVPs
8.4. Reused from RFC 4675 8.4. Reused AVPs from RFC 4675
The following AVPs are reused from "RADIUS Attributes for Virtual LAN The following AVPs are reused from "RADIUS Attributes for Virtual LAN
and Priority Support" specification [RFC4675]. and Priority Support" specification [RFC4675].
+---------------------+ +---------------------+
| 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 |
+------------------+------+------------|----+-----+----+-----|----+ +------------------+------+------------|----+-----+----+-----|----+
Figure 11: Reused attributes from RFC 4675 Figure 12: Reused attributes from RFC 4675
8.5. Reused from Diameter QoS Application 8.5. Reused AVPs from Diameter QoS Application
The following AVPs are reused from the Traffic Classification and The following AVPs are reused from the Traffic Classification and
Quality of Service (QoS) Attributes for Diameter [RFC5777]. Quality of Service (QoS) Attributes for Diameter [RFC5777].
+-------------------+ +-------------------+
| AVP Flag rules | | AVP Flag rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP | | | May | | AVP | | | May |
| Attribute Name Code Data Type |MUST |MAY| encrypt | | Attribute Name Code Data Type |MUST |MAY| encrypt |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|Port TBD Integer32 | M | P | Y | |Port TBD Integer32 | M | P | Y |
|IP-Address-Mask TBD Grouped | M | P | Y | |IP-Address-Mask TBD Grouped | M | P | Y |
|Protocol TBD Enumerated | M | P | Y | |Protocol TBD Enumerated | M | P | Y |
|Direction TBD Enumerated | M | P | Y | |Direction TBD Enumerated | M | P | Y |
skipping to change at page 28, line 22 skipping to change at page 31, line 26
|IP-Address-Mask TBD Grouped | M | P | Y | |IP-Address-Mask TBD Grouped | M | P | Y |
|Protocol TBD Enumerated | M | P | Y | |Protocol TBD Enumerated | M | P | Y |
|Direction TBD Enumerated | M | P | Y | |Direction TBD Enumerated | M | P | Y |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|M - Mandatory bit. An AVP with "M" bit set and its value MUST be | |M - Mandatory bit. An AVP with "M" bit set and its value MUST be |
| supported and recognized by a Diameter entity in order the | | supported and recognized by a Diameter entity in order the |
| message, which carries this AVP, to be accepted. | | message, which carries this AVP, to be accepted. |
|P - Indicates the need for encryption for end-to-end security. | |P - Indicates the need for encryption for end-to-end security. |
+-------------------------------------------------------------------+ +-------------------------------------------------------------------+
Figure 12: Reused QoS-attributes Figure 13: Reused QoS-attributes
8.6. Reused from ETSI ES 283 034, e4 Diameter Application 8.6. Reused AVPs from ETSI ES 283 034, e4 Diameter Application
The following AVPs are reused from the Diameter e4 Application The following AVPs are reused from the Diameter e4 Application
[ETSIES283034]. [ETSIES283034].
+-------------------+ +-------------------+
| AVP Flag rules | | AVP Flag rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP | | | May | | AVP | | | May |
| Attribute Name Code Data Type |MUST |MAY| encrypt | | Attribute Name Code Data Type |MUST |MAY| encrypt |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|Address-Realm 301 OctetString | M,V | | Y | |Address-Realm 301 OctetString | M,V | | Y |
skipping to change at page 28, line 47 skipping to change at page 31, line 51
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|M - Mandatory bit. An AVP with "M" bit set and its value MUST be | |M - Mandatory bit. An AVP with "M" bit set and its value MUST be |
| supported and recognized by a Diameter entity in order the | | supported and recognized by a Diameter entity in order the |
| message, which carries this AVP, to be accepted. | | message, which carries this AVP, to be accepted. |
|P - Indicates the need for encryption for end-to-end security. | |P - Indicates the need for encryption for end-to-end security. |
|V - Indicates whether the optional Vendor-ID field is present | |V - Indicates whether the optional Vendor-ID field is present |
| in the AVP header. Vendor-Id header of all AVPs in | | in the AVP header. Vendor-Id header of all AVPs in |
| this table will be set to ETSI (13019). | | this table will be set to ETSI (13019). |
+-------------------------------------------------------------------+ +-------------------------------------------------------------------+
Figure 13: Reused AVPs from Diameter e4 application Figure 14: Reused AVPs from Diameter e4 application
8.7. DNCA Defined AVPs 8.7. DNCA Defined AVPs
The following table describes the new Diameter AVPs used in this The following table describes the new Diameter AVPs used in this
document. document.
+-------------------+ +-------------------+
| AVP Flag rules | | AVP Flag rules |
+-----------------------------------------------|-----+---+---------+ +-----------------------------------------------|-----+---+---------+
| AVP Section | | | May | | AVP Section | | | May |
| Attribute Name Code Defined Data Type |MUST |MAY| encrypt | | Attribute Name Code Defined Data Type |MUST |MAY| encrypt |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|NC-Request-Type TBD 7.7.1 Enumerated | M | P | Y | |NC-Request-Type TBD 8.7.1 Enumerated | M | P | Y |
|NAT-Control-Install TBD 7.7.2 Grouped | M | P | Y | |NAT-Control-Install TBD 8.7.2 Grouped | M | P | Y |
|NAT-Control-Remove TBD 7.7.3 Grouped | M | P | Y | |NAT-Control-Remove TBD 8.7.3 Grouped | M | P | Y |
|NAT-Control-Definition TBD 7.7.4 Grouped | M | P | Y | |NAT-Control-Definition TBD 8.7.4 Grouped | M | P | Y |
|NAT-Internal-Address TBD 7.7.5 Grouped | M | P | Y | |NAT-Internal-Address TBD 8.7.5 Grouped | M | P | Y |
|NAT-External-Address TBD 7.7.6 Grouped | M | P | Y | |NAT-External-Address TBD 8.7.6 Grouped | M | P | Y |
|Max-NAT-Bindings TBD 7.7.7 Unsigned32 | M | P | Y | |Max-NAT-Bindings TBD 8.7.7 Unsigned32 | M | P | Y |
|NAT-Control- TBD 7.7.8 OctetString| M | P | Y | |NAT-Control- TBD 8.7.8 OctetString| M | P | Y |
| Binding-Rule | | | | | Binding-Rule | | | |
|Duplicate- TBD 7.7.9 UTF8String | M | P | Y | |Duplicate- TBD 8.7.9 UTF8String | M | P | Y |
| Session-ID | | | | | Session-ID | | | |
|NAT-Control-Record TBD 8.2.1 Grouped | M | P | Y | |NAT-Control-Record TBD 9.2.1 Grouped | M | P | Y |
|NAT-Control- TBD 8.2.2 Enumerated | M | P | Y | |NAT-Control- TBD 9.2.2 Enumerated | M | P | Y |
| Binding-Status | | | | | Binding-Status | | | |
|Current-NAT-Bindings TBD 8.2.3 Unsigned32 | M | P | Y | |Current-NAT-Bindings TBD 9.2.3 Unsigned32 | M | P | Y |
+-----------------------------------------------+-----+---+---------+ +-----------------------------------------------+-----+---+---------+
|M - Mandatory bit. An AVP with "M" bit set and its value MUST be | |M - Mandatory bit. An AVP with "M" bit set and its value MUST be |
| supported and recognized by a Diameter entity in order the | | supported and recognized by a Diameter entity in order the |
| message, which carries this AVP, to be accepted. | | message, which carries this AVP, to be accepted. |
|P - Indicates the need for encryption for end-to-end security. | |P - Indicates the need for encryption for end-to-end security. |
|V - Vendor specific bit that indicates whether the optional |
| Vendor-ID field is present in the AVP header. |
+-------------------------------------------------------------------+ +-------------------------------------------------------------------+
Figure 14: New Diameter AVPs Figure 15: New Diameter AVPs
8.7.1. NC-Request-Type AVP 8.7.1. NC-Request-Type AVP
The NC-Request-Type AVP (AVP Code TBD) is of type Enumerated and The NC-Request-Type AVP (AVP Code TBD) 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 used to install binding at DNCA Agent on An Initial Request is to initiate a Diameter NAT control
a successful access session setup. 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 (4) QUERY_REQUEST (3)
Query Request is used to query DNCA Agent 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) is of type Grouped, and it is used The NAT-Control AVP (AVP code TBD) is of type Grouped, and it is used
to activate or install NAT bindings. It also contains Max-NAT- to activate or install NAT bindings. It also contains Max-NAT-
Bindings that defines maximum number of NAT bindings to be allowed Bindings that defines the maximum number of NAT bindings to be
for a subscriber and NAT-Control-Binding-Rule that references allowed for a subscriber and the NAT-Control-Binding-Rule that
predefined policy template on DNCA Agent that may contain static references a predefined policy template on the NAT-device that may
bindings, maximum number of bindings to be allowed, address pool from contain static binding, a maximum number of bindings allowed, an IP-
which external binding address should be allocated. address pool from which external binding addresses should be
allocated.
AVP format: AVP format:
NAT-Control-Install ::= < AVP Header: TBD > NAT-Control-Install ::= < AVP Header: TBD >
* [ NAT-Control-Definition ] * [ NAT-Control-Definition ]
[ NAT-Control-Binding-Rule ] [ NAT-Control-Binding-Rule ]
[ Max-NAT-Bindings] [ Max-NAT-Bindings]
* [ AVP ] * [ AVP ]
8.7.3. NAT-Control-Remove AVP 8.7.3. NAT-Control-Remove AVP
The NAT-Control-Remove AVP (AVP code TBD) is of type Grouped, and it The NAT-Control-Remove AVP (AVP code TBD) is of type Grouped, and it
is used to deactivate or remove NAT bindings. is used to deactivate or remove NAT-bindings.
AVP format: AVP format:
NAT-Control-Remove ::= < AVP Header: TBD > NAT-Control-Remove ::= < AVP Header: TBD >
* [ NAT-Control-Definition ] * [ NAT-Control-Definition ]
[ NAT-Control-Binding-Rule ] [ NAT-Control-Binding-Rule ]
* [ AVP ] * [ AVP ]
8.7.4. NAT-Control-Definition AVP 8.7.4. NAT-Control-Definition AVP
The NAT-Control-Definition AVP (AVP code TBD) is of type Grouped, and The NAT-Control-Definition AVP (AVP code TBD) is of type Grouped, 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 DNCA Agent and DNCA Manager. 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 pre-defined binding.
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 address are specified then the binding reserves the and external IP-address are specified then the binding reserves the
addresses for all transport protocols. 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, NAT- context are: "IN","OUT". If Direction AVP is OUT or absent, the NAT-
Internal-Address refers to the address of the subscriber device that Internal-Address refers to the IP-address of the endpoint that needs
needs to be translated. If Direction AVP is "IN", NAT-Internal- to be translated. If Direction AVP is "IN", NAT-Internal-Address is
Address is the destination 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 > NAT-Control-Definition ::= < AVP Header: TBD >
{ 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) is of type Grouped. It The NAT-Internal-Address AVP (AVP code TBD) is of type Grouped. 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. IPV6-Prefix and Framed-IP-Address AVPs are mutually exclusive.
AVP format: AVP format:
NAT-Internal-Address ::= < AVP Header: TBD > NAT-Internal-Address ::= < AVP Header: TBD >
[ 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) is of type Grouped, and The NAT-External-Address AVP (AVP code TBD) is of type Grouped, and
it describes the external IP address and port for a binding. IP- it describes the external IP-address and port for a binding. IP-
Address-Mask AVP can only be specified when Framed-IP-Address AVP is Address-Mask AVP can only be specified when the Framed-IP-Address AVP
present. External IP address specified in this attribute can be is present. The external IP-address specified in this attribute can
reused for multiple subscribers by specifying the same address in the be reused for multiple endpoints by specifying the same address in
respective NAT-External-Address AVPs. the respective NAT-External-Address AVPs.
AVP format: AVP format:
NAT-External-Address ::= < AVP Header: TBD > NAT-External-Address ::= < AVP Header: TBD >
[ Framed-IP-Address ] [ Framed-IP-Address ]
[ IP-Address-Mask ] [ IP-Address-Mask ]
[ Port ] [ Port ]
* [ AVP ] * [ AVP ]
8.7.7. Max-NAT-Bindings 8.7.7. Max-NAT-Bindings
The Max-NAT-Bindings AVP (AVP code TBD) is of type Unsigned32. It The Max-NAT-Bindings AVP (AVP code TBD) is of type Unsigned32. It
indicates the maximum number of NAT bindings allowed. indicates the maximum number of NAT-bindings allowed for a particular
endpoint.
8.7.8. NAT-Control-Binding-Rule AVP 8.7.8. NAT-Control-Binding-Rule AVP
The NAT-Control-Binding-Rule AVP (AVP code TBD) is of type The NAT-Control-Binding-Rule AVP (AVP code TBD) is of type
OctetString. It defines a name for a policy template that will be OctetString. It defines a name for a policy template that is
predefined at NAT. Details on the contents and structure of the predefined at the NAT-device. Details on the contents and structure
template and configuration are outside the scope of this document. of the template and configuration are outside the scope of this
The policy to which this AVP refers to may contain NAT bindings, document. The policy to which this AVP refers to may contain NAT-
address pool for external address allocation of NAT binding, and bindings, IP-address pool for allocating the external IP-address of a
maximum allowed NAT bindings. Such policy template can be reused by NAT-binding, and maximum number of allowed NAT-bindings. Such policy
specifying same NAT-Control-Binding-Rule AVP in corresponding NAT- template can be reused by specifying the same NAT-Control-Binding-
Control-Install AVPs of multiple subscribers. Rule AVP in the corresponding NAT-Control-Install AVPs of multiple
endpoints.
8.7.9. Duplicate-Session-Id AVP 8.7.9. Duplicate-Session-Id AVP
The Duplicate-Session-Id AVP (AVP Code TBD) is of type UTF8String. The Duplicate-Session-Id AVP (AVP Code TBD) is of type UTF8String.
It is used to report error and contains the Session-Id of an existing It is used to report errors and contains the Session-Id of an
session. existing session.
9. Accounting Commands 9. Accounting Commands
DNCA reuses session based accounting as defined in Diameter Base The DNCA reuses session based accounting as defined in the Diameter
Protocol[RFC3588] to report the bindings per endpoint. This Base Protocol[RFC3588] to report the bindings per endpoint. This
reporting is achieved by sending Diameter Accounting Requests (ACR) reporting is achieved by sending Diameter Accounting Requests (ACR)
[Start, Interim and Stop] from DNCA Agent to DNCA Manager. [Start, Interim and Stop] from the DNCA Diameter peer within the NAT-
device to its associated DNCA Diameter peer within the NAT-
controller.
DNCA Agent sends an ACR Start on receiving an NCR with NC-Request- The DNCA Diameter peer within the NAT-device sends an ACR Start on
Type AVP set to INITIAL_REQUEST for a session or on creation of the receiving a NCR with NC-Request-Type AVP set to INITIAL_REQUEST for a
first binding for a session requested in an earlier NCR. DNCA may session or on creation of the first binding for a session requested
send ACR Interim updates, if required, either due to a change in in an earlier NCR. DNCA may send ACR Interim updates, if required,
bindings resulting from a NCR with NC-Request-Type AVP set to either due to a change in bindings resulting from a NCR with NC-
UPDATE_REQUEST, or periodically as specified in Acct-Interim-Interval Request-Type AVP set to UPDATE_REQUEST, or periodically as specified
by DNCA Manager, or when it creates or tears down bindings. An ACR in Acct-Interim-Interval by the DNCA Diameter peer within the NAT-
Stop is sent by DNCA Agent on receiving STR. 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
STR.
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.
DNCA Agent may trigger an interim accounting record when maximum The DNCA Diameter peer within the NAT-device may trigger an interim
number of bindings, if received in NCR, is reached. accounting record when maximum number of bindings, if received in
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 Diameter Base The ACR and ACA messages are reused as defined in Diameter Base
Protocol [RFC3588] for exchanging endpoint NAT binding details Protocol [RFC3588] for exchanging endpoint NAT binding details
between DNCA Agent and DNCA Manager. DNCA Application ID is used in between the DNCA Diameter peers. DNCA Application ID is used in the
the accounting commands. ACR contains one or more optional NAT- accounting commands. ACR contains one or more optional NAT-Control-
Control-Record AVP to report the bindings. DNCA Agent indicates the Record AVP to report the bindings. The NAT-device indicates the
number of allocated NAT bindings to DNCA Manager using the Current- number of allocated NAT bindings to NAT-controller using the Current-
NAT-Bindings AVP. This number needs to match the number of bindings NAT-Bindings AVP. This number needs to match the number of bindings
identified as active within the NAT-Control-Record AVP. 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], DNCA Agent must In addition to AVPs for ACR specified in [RFC3588], the DNCA Diameter
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) is of type Grouped. It The NAT-Control-Record AVP (AVP code TBD) 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.
skipping to change at page 34, line 4 skipping to change at page 37, line 10
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) is of type Unsigned32. The Current-NAT-Bindings AVP (AVP code TBD) is of type Unsigned32.
It indicates number of NAT bindings active on NAT device. It indicates number of NAT bindings active on NAT-device.
10. AVP Occurrence Table 10. AVP Occurrence Table
The following sections presents the AVPs defined in this document and The following sections presents the AVPs defined in this document and
specifies the Diameter messages in which, they MAY be present. Note: specifies the Diameter messages in which, they MAY 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:
skipping to change at page 35, line 51 skipping to change at page 38, line 51
+-----------------------------------+-------------------+ +-----------------------------------+-------------------+
| 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 the namespaces that have either been created in
this specification or had their values assigned to existing this specification, or the values assigned to existing namespaces
namespaces managed by IANA. managed by IANA.
11.1. Command Codes
IANA is requested to allocate command code values for the following. In the subsections below, when we speak about review by a Designated
Expert, please note that the designated expert will be assigned by
the IESG. Initially, such Expert discussions take place on the AAA
WG mailing list.
Registry: 11.1. Application Identifier
+------------+-----------------------------------+------------------+ This specification assigns the value <TBD>, 'Diameter NAT Control
| Code Value | Name | Reference | Application', to the Application Identifier namespace defined in
+------------+-----------------------------------+------------------+ [RFC3588]. See Section 4 for more information.
| to be | NAT-Control-Request (NCR), | Section 6.1, |
| assigned | NAT-Control-Answer (NCA) | Section 6.2 |
+------------+-----------------------------------+------------------+
Table 1: Command codes 11.2. Command Codes
11.2. AVP Codes This specification uses the value <TBD> from the Command code
namespace defined in [RFC3588] for the NAT-Control-Request (NCR),
NAT-Control-Answer (NCA) commands. See Section 6.1 and Section 6.2
for more information on these commands.
IANA is requested to allocate AVP codes for the following AVPs that 11.3. AVP Codes
are defined in this document.
Registry: This specification assigns the values <TBD> from the AVP code
namespace defined in [RFC3588]. See Figure 15for the assignment of
the namespace in this specification.
+----------------+----------------------------+---------------+ 11.4. Result-Code AVP Values
| Code Value | Name | Reference |
+----------------+----------------------------+---------------+
| to be assigned | NC-Request-Type | Section 8.7.1 |
| to be assigned | NAT-Control-Install | Section 8.7.2 |
| to be assigned | NAT-Control-Remove | Section 8.7.3 |
| to be assigned | NAT-Control-Definition | Section 8.7.4 |
| to be assigned | NAT-Internal-Address | Section 8.7.5 |
| to be assigned | NAT-External-Address | Section 8.7.6 |
| to be assigned | Max-NAT-Bindings | Section 8.7.7 |
| to be assigned | NAT-Control-Binding-Rule | Section 8.7.8 |
| to be assigned | Duplicate-Session-Id | Section 8.7.9 |
| to be assigned | NAT-Control-Record | Section 9.2.1 |
| to be assigned | NAT-Control-Binding-Status | Section 9.2.2 |
| to be assigned | Current-NAT-Bindings | Section 9.2.3 |
+----------------+----------------------------+---------------+
Table 2: AVP codes This specification assigns the values <TBD> (4xxx, 5xxx, 5xxx, 5xxx,
5xxx,5xxx) from the Result-Code AVP value namespace defined in
[RFC3588]. See Section 8.2 for the assignment of the namespace in
this specification.
11.3. AVP Values 11.5. NC-Request-Type AVP
11.3.1. Result-Code AVP Values
Section 8.2 defines several new values for the Result-Code AVP for As defined in Section 8.7.1, the NC-Request-Type AVP includes
transient and permanent failures. IANA is requested to allocate the Enumerated type values 1 - 3. IANA has created and is maintaining a
corresponding values from the ranges for transient (4xxx) and namespace for this AVP. All remaining values are available for
permantent (5xxx) failures. assignment by a Designated Expert [RFC5226].
+-----------+---------------------------------------+---------------+ 11.6. NAT-Control-Binding-Status AVP
| Code | Name | Reference |
| Value | | |
+-----------+---------------------------------------+---------------+
| to be | RESOURCE_FAILURE | Section 8.2.2 |
| assigned | | |
| (4xxx) | | |
| to be | UNKNOWN_BINDING_RULE_NAME | Section 8.2.3 |
| assigned | | |
| (5xxx) | | |
| to be | BINDING_FAILURE | Section 8.2.3 |
| assigned | | |
| (5xxx) | | |
| to be | MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT | Section 8.2.3 |
| assigned | | |
| (5xxx) | | |
| to be | SESSION_EXISTS | Section 8.2.3 |
| assigned | | |
| (5xxx) | | |
| to be | INSUFFICIENT_CLASSIFIERS | Section 8.2.3 |
| assigned | | |
| (5xxx) | | |
+-----------+---------------------------------------+---------------+
Table 3: Result Code AVP Values As defined in Section 8.7.1, the NAT-Control-Binding-Status AVP
includes Enumerated type values 1 - 3. IANA has created and is
maintaining a namespace for this AVP. All remaining values are
available for assignment by a Designated Expert [RFC5226].
11.4. Application IDs 12. Security Considerations
IANA is requested to allocate the following application ID using the This document describes procedures for controlling NAT related
next value from the 7-16777215 range. attributes and parameters by an entity, which is non-local to the
device performing NAT. This section discusses security
considerations for DNCA interactions between the Diameter peers
within a NAT-controller and a NAT-device. Security between NAT-
controller and NAT-device has a number of components: authentication,
authorization, integrity, and confidentiality.
Registry: Authentication refers to confirming the identity of an originator for
all datagrams received from the originator. Lack of authentication
of Diameter messages between the Diameter peers can jeopardize the
fundamental service of the peering network elements. A consequence
of not authenticating the message sender by the recipient would be
that an attacker could spoof the identity of a "legitimate"
authorizing entity in order to change the behavior of the receiver.
An attacker could for example launch a denial of service attack by
setting the maximum number of bindings for a session on the NAT-
device to zero; provision bindings on a NAT-device which include IP-
addresses already in use in other parts of the network; or request
session termination of the Diameter session and hamper a user's
connectivity. Lack of authentication of a NAT-device to a NAT-
controller could lead to situations where the NAT-device could
provide a wrong view of the resources (i.e. NAT-bindings). In
addition, templates on the NAT-device specifying pre-defined binding
rules could be configured differently than expected by the NAT-
controller. Failing of any of the two DNCA Diameter peers to provide
the required credentials should be subject to logging.
+----------------+----------------------------------+-----------+ Authorization refers to whether a particular authorizing entity is
| ID Value | Name | Reference | authorized to signal a network element requests for one or more
+----------------+----------------------------------+-----------+ applications, adhering to a certain policy profile. Failing the
| to be assigned | Diameter NAT Control Application | Section 4 | authorization process might indicate a resource theft attempt or
+----------------+----------------------------------+-----------+ failure due to administrative and/or credential deficiencies. In
either case, the network element should take the proper measures to
log such attempts.
Table 4: Diameter Application ID values Integrity is required to ensure that a Diameter message exchanged
between the Diameter peers has not been maliciously altered by
intermediate devices. The result of a lack of data integrity
enforcement in an untrusted environment could be that an impostor
will alter the messages exchanged between the peers. This could
cause a change of behavior of the peers, including the potential of a
denial of service.
12. Security Considerations Confidentiality protection of Diameter messages ensures that the
signaling data is accessible only to the authorized entities. When
signaling messages between the DNCA Diameter peers traverse untrusted
networks, lack of confidentiality will allow eavesdropping and
traffic analysis.
Similar to the impact of Diameter QoS application (see [RFC5866]) on Diameter offers security mechanisms to deal with the functionality
authorization of QoS reservations, this document describes procedures demanded above. DNCA makes use of the capabilities offered by
for authorizing NAT related attributes and parameters by an entity, Diameter and the underlying transport protocols to deliver these
which is non-local to the device performing NAT. The security requirements (see Section 5.1 ). If the DNCA communication traverses
considerations for the Diameter QoS application (see [RFC5866] untrusted networks, it is assumed that messages between DNCA Diameter
section 11) apply in a similar way to DNCA. To secure the peers are secured using either IPsec or TLS. Please refer to
information exchange between the authorizing entity (DNCA Manager) [RFC3588], section 13 for details. DNCA Diameter peers MAY perform
and the NAT device (DNCA Agent) requires bilateral authentication of bilateral authentication, authorization as well as procedures to
the involved parties, authorization of the involved parties to ensure integrity and confidentiality of the information exchange.
perform the required procedures and functions, and procedures to
ensure integrity and confidentiality of the information exchange MAY
be performed. DNCA makes use of the capabilities offered by Diameter
and the underlying transport protocols to deliver these requirements
(see Section 5.1 ).
It is assumed that DNCA Agent and DNCA Manager are in the same domain It is assumed that the DNCA Diameter peers are typically in the same
and have a mutual trust set up. Authorization between DNCA Agent and domain and have a mutual trust set up. This document does not
DNCA Manager is beyond the scope of this document. specify a mechanisms for authorization between the DNCA Diameter
peers. It is assumed that the DNCA Diameter peers are provided with
sufficient information to make an authorization decision. The
information can come from various sources, for example the peering
devices could store local authentication policy, listing the
identities of authorized peers.
13. Acknowledgements 13. Acknowledgements
The authors would like to thank Jouni Korhonen, Avi Lior, Chris Metz, The authors would like to thank Miguel A. Garcia, Jouni Korhonen,
Pallavi Mishra, Lionel Morand, Hannes Tschofenig, Shashank Vikram, Matt Lepinski, Avi Lior, Chris Metz, Pallavi Mishra, Lionel Morand,
Greg Weber, and Glen Zorn for their input on this document. Hannes Tschofenig, Shashank Vikram, Greg Weber, and Glen Zorn for
their input on this document.
14. Change History (to be removed prior to publication as an RFC) 14. Change History (to be removed prior to publication as an RFC)
Changes from -00 to -01 Changes from -00 to -01
a. new values for Result-Code AVP used - instead of Experimental- a. new values for Result-Code AVP used - instead of Experimental-
Result AVP Result AVP
b. added support for transport specific binding (UDP/TCP) b. added support for transport specific binding (UDP/TCP)
skipping to change at page 39, line 19 skipping to change at page 42, line 21
d. Editorial changes d. Editorial changes
e. added support for bindings providing AFT (NAT64) e. added support for bindings providing AFT (NAT64)
Changes from -02 to -03 Changes from -02 to -03
a. Editorial changes a. Editorial changes
Changes from -03 to -04 Changes from -03 to -04
a. Editorial changes suggested in WG Lastcall review a. Editorial changes suggested in WG last call review
b. Removed NCR Request type terminate and replaced with STR b. Removed NCR Request type terminate and replaced with STR
c. All references to Auth-Session-State are removed and a new c. All references to Auth-Session-State are removed and a new
section to describe FSM for Manager and Agent has been added section to describe FSM for Manager and Agent has been added
d. Clarified reuse of External address and address pools among d. Clarified reuse of External address and address pools among
multiple subscribers multiple subscribers
Changes from -04 to -05 Changes from -04 to -05
skipping to change at page 39, line 47 skipping to change at page 42, line 49
Changes from -06 to -07 Changes from -06 to -07
a. Added a note in section 4.3 stating the state of pre-existing a. Added a note in section 4.3 stating the state of pre-existing
bindings on update failure bindings on update failure
b. Security considerations are made consistent between sections 5.1 b. Security considerations are made consistent between sections 5.1
and 12 and 12
c. Editorial changes c. Editorial changes
15. References Changes from -07 to -08
15.1. Normative References 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).
15. Normative References
[ETSIES283034] [ETSIES283034]
ETSI, "Telecommunications and Internet Converged Services ETSI, "Telecommunications and Internet Converged Services
and Protocols for Advanced Networks (TISPAN),Network and Protocols for Advanced Networks (TISPAN),Network
Attachment Sub-System (NASS),e4 interface based on the Attachment Sub-System (NASS),e4 interface based on the
Diameter protocol.", September 2008. Diameter protocol.", 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.
skipping to change at page 40, line 26 skipping to change at page 43, line 39
Arkko, "Diameter Base Protocol", RFC 3588, September 2003. Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
"Diameter Network Access Server Application", RFC 4005, "Diameter Network Access Server Application", RFC 4005,
August 2005. August 2005.
[RFC4675] Congdon, P., Sanchez, M., and B. Aboba, "RADIUS Attributes [RFC4675] Congdon, P., Sanchez, M., and B. Aboba, "RADIUS Attributes
for Virtual LAN and Priority Support", RFC 4675, for Virtual LAN and Priority Support", RFC 4675,
September 2006. September 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M., [RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M.,
and A. Lior, "Traffic Classification and Quality of and A. Lior, "Traffic Classification and Quality of
Service (QoS) Attributes for Diameter", RFC 5777, Service (QoS) Attributes for Diameter", RFC 5777,
February 2010. February 2010.
15.2. Informative References
[RFC5866] Sun, D., McCann, P., Tschofenig, H., Tsou, T., Doria, A.,
and G. Zorn, "Diameter Quality-of-Service Application",
RFC 5866, May 2010.
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
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