--- 1/draft-ietf-dime-nat-control-06.txt 2011-02-16 16:17:23.000000000 +0100 +++ 2/draft-ietf-dime-nat-control-07.txt 2011-02-16 16:17:23.000000000 +0100 @@ -1,22 +1,22 @@ Internet Engineering Task Force F. Brockners Internet-Draft S. Bhandari Intended status: Standards Track Cisco -Expires: July 14, 2011 V. Singh +Expires: August 20, 2011 V. Singh V. Fajardo Telcordia Technologies - January 10, 2011 + February 16, 2011 Diameter Network Address and Port Translation Control Application - draft-ietf-dime-nat-control-06 + draft-ietf-dime-nat-control-07 Abstract This document describes the framework, messages, and procedures for the Diameter Network address and port translation Control Application. This Diameter application allows per endpoint control of Network Address Translators and Network Address and Port Translators, which are added to cope with IPv4-address space completion. This Diameter application allows external devices to configure and manage a Network Address Translator device - expanding @@ -42,21 +42,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on July 14, 2011. + This Internet-Draft will expire on August 20, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -83,66 +83,66 @@ 4.6. DNCA Manager and Agent Failures . . . . . . . . . . . . . 18 5. Use Of The Diameter Base Protocol . . . . . . . . . . . . . . 18 5.1. Securing Diameter Messages . . . . . . . . . . . . . . . . 19 5.2. Accounting Functionality . . . . . . . . . . . . . . . . . 19 5.3. Use Of Sessions . . . . . . . . . . . . . . . . . . . . . 19 5.4. Routing Considerations . . . . . . . . . . . . . . . . . . 19 5.5. Advertising Application Support . . . . . . . . . . . . . 19 6. DNCA Commands . . . . . . . . . . . . . . . . . . . . . . . . 20 6.1. NAT-Control Request (NCR) Command . . . . . . . . . . . . 20 6.2. NAT-Control Answer (NCA) Command . . . . . . . . . . . . . 21 - 7. NAT Control Application Session State Machine . . . . . . . . 22 - 8. DNCA AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . 25 - 8.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 25 - 8.2. Additional Result-Code AVP Values . . . . . . . . . . . . 26 - 8.2.1. Success . . . . . . . . . . . . . . . . . . . . . . . 26 - 8.2.2. Transient Failures . . . . . . . . . . . . . . . . . . 26 - 8.2.3. Permanent Failures . . . . . . . . . . . . . . . . . . 27 - 8.3. Reused NASREQ Diameter Application AVPs . . . . . . . . . 28 - 8.4. Reused from RFC 4675 . . . . . . . . . . . . . . . . . . . 28 - 8.5. Reused from Diameter QoS Application . . . . . . . . . . . 28 - 8.6. Reused from ETSI ES 283 034, e4 Diameter Application . . . 29 - 8.7. DNCA Defined AVPs . . . . . . . . . . . . . . . . . . . . 30 - 8.7.1. NC-Request-Type AVP . . . . . . . . . . . . . . . . . 30 - 8.7.2. NAT-Control-Install AVP . . . . . . . . . . . . . . . 31 - 8.7.3. NAT-Control-Remove AVP . . . . . . . . . . . . . . . . 31 - 8.7.4. NAT-Control-Definition AVP . . . . . . . . . . . . . . 31 - 8.7.5. NAT-Internal-Address AVP . . . . . . . . . . . . . . . 32 - 8.7.6. NAT-External-Address AVP . . . . . . . . . . . . . . . 32 - 8.7.7. Max-NAT-Bindings . . . . . . . . . . . . . . . . . . . 33 - 8.7.8. NAT-Control-Binding-Rule AVP . . . . . . . . . . . . . 33 - 8.7.9. Duplicate-Session-Id AVP . . . . . . . . . . . . . . . 33 - 9. Accounting Commands . . . . . . . . . . . . . . . . . . . . . 33 - 9.1. NAT Control Accounting Messages . . . . . . . . . . . . . 34 - 9.2. NAT Control Accounting AVPs . . . . . . . . . . . . . . . 34 - 9.2.1. NAT-Control-Record . . . . . . . . . . . . . . . . . . 34 - 9.2.2. NAT-Control-Binding-Status . . . . . . . . . . . . . . 34 - 9.2.3. Current-NAT-Bindings . . . . . . . . . . . . . . . . . 35 - 10. AVP Occurrence Table . . . . . . . . . . . . . . . . . . . . . 35 + 7. NAT Control Application Session State Machine . . . . . . . . 21 + 8. DNCA AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . 24 + 8.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 24 + 8.2. Additional Result-Code AVP Values . . . . . . . . . . . . 25 + 8.2.1. Success . . . . . . . . . . . . . . . . . . . . . . . 25 + 8.2.2. Transient Failures . . . . . . . . . . . . . . . . . . 25 + 8.2.3. Permanent Failures . . . . . . . . . . . . . . . . . . 26 + 8.3. Reused NASREQ Diameter Application AVPs . . . . . . . . . 27 + 8.4. Reused from RFC 4675 . . . . . . . . . . . . . . . . . . . 27 + 8.5. Reused from Diameter QoS Application . . . . . . . . . . . 27 + 8.6. Reused from ETSI ES 283 034, e4 Diameter Application . . . 28 + 8.7. DNCA Defined AVPs . . . . . . . . . . . . . . . . . . . . 29 + 8.7.1. NC-Request-Type AVP . . . . . . . . . . . . . . . . . 29 + 8.7.2. NAT-Control-Install AVP . . . . . . . . . . . . . . . 30 + 8.7.3. NAT-Control-Remove AVP . . . . . . . . . . . . . . . . 30 + 8.7.4. NAT-Control-Definition AVP . . . . . . . . . . . . . . 30 + 8.7.5. NAT-Internal-Address AVP . . . . . . . . . . . . . . . 31 + 8.7.6. NAT-External-Address AVP . . . . . . . . . . . . . . . 31 + 8.7.7. Max-NAT-Bindings . . . . . . . . . . . . . . . . . . . 32 + 8.7.8. NAT-Control-Binding-Rule AVP . . . . . . . . . . . . . 32 + 8.7.9. Duplicate-Session-Id AVP . . . . . . . . . . . . . . . 32 + 9. Accounting Commands . . . . . . . . . . . . . . . . . . . . . 32 + 9.1. NAT Control Accounting Messages . . . . . . . . . . . . . 33 + 9.2. NAT Control Accounting AVPs . . . . . . . . . . . . . . . 33 + 9.2.1. NAT-Control-Record . . . . . . . . . . . . . . . . . . 33 + 9.2.2. NAT-Control-Binding-Status . . . . . . . . . . . . . . 33 + 9.2.3. Current-NAT-Bindings . . . . . . . . . . . . . . . . . 34 + 10. AVP Occurrence Table . . . . . . . . . . . . . . . . . . . . . 34 10.1. DNCA AVP Table for NAT Control Initial and Update - Requests . . . . . . . . . . . . . . . . . . . . . . . . . 35 - 10.2. DNCA AVP Table for Session Query request . . . . . . . . . 36 - 10.3. DNCA AVP Table for Accounting Message . . . . . . . . . . 36 - 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36 - 11.1. Command Codes . . . . . . . . . . . . . . . . . . . . . . 37 - 11.2. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 37 - 11.3. AVP Values . . . . . . . . . . . . . . . . . . . . . . . . 37 - 11.3.1. Result-Code AVP Values . . . . . . . . . . . . . . . . 38 - 11.4. Application IDs . . . . . . . . . . . . . . . . . . . . . 38 - 12. Security Considerations . . . . . . . . . . . . . . . . . . . 39 - 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 39 + Requests . . . . . . . . . . . . . . . . . . . . . . . . . 34 + 10.2. DNCA AVP Table for Session Query request . . . . . . . . . 35 + 10.3. DNCA AVP Table for Accounting Message . . . . . . . . . . 35 + 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 + 11.1. Command Codes . . . . . . . . . . . . . . . . . . . . . . 36 + 11.2. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 36 + 11.3. AVP Values . . . . . . . . . . . . . . . . . . . . . . . . 36 + 11.3.1. Result-Code AVP Values . . . . . . . . . . . . . . . . 37 + 11.4. Application IDs . . . . . . . . . . . . . . . . . . . . . 37 + 12. Security Considerations . . . . . . . . . . . . . . . . . . . 38 + 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 38 14. Change History (to be removed prior to publication as an - RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 + RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40 15.1. Normative References . . . . . . . . . . . . . . . . . . . 40 - 15.2. Informative References . . . . . . . . . . . . . . . . . . 41 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41 + 15.2. Informative References . . . . . . . . . . . . . . . . . . 40 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 40 1. Introduction Internet service providers have started to deploy Network Address Translators (NATs) and Network Address and Port Translators (NAPTs) at the edge of their networks to deal with the depletion of available public IPv4 addresses. This document defines a Diameter application for providers deploying such NAT and NAPT devices. The use of a Diameter application allows for simple integration into the existing Authentication, Authorization and Accounting (AAA) environment of a @@ -180,35 +180,33 @@ list of IP-subnets. Such External address pools can be used to select external IP address in NAPT/NAT bindings for multiple subscribers. 4. Generates reports and accounting records: Reports established bindings for a particular user. The collected information is used by accounting systems for statistical purposes. 5. Queries and retrieves details about bindings on demand: This feature complements the previously mentioned accounting - functionality(see item 4). The query functionality complements - alternative information query mechanisms, such as Simple Network - Management Protocol (SNMP) based mechanisms, if available. + functionality(see item 4). 6. Identifies a subscriber or endpoint on multiple network devices (NAPT or NAT device, the AAA-server, or the Network Access Server (NAS)): Endpoint identification is facilitated through a Global Endpoint ID. Endpoints are identified through a single or a set of classifiers, such as IP address, Virtual Local Area Network (VLAN) identifier, or interface identifier which uniquely identify the traffic associated with a particular global endpoint This document is structured as follows: Section 2 lists terminology, - while Section 3 provides an introduction to the DNCA and its overall - deployment framework. Sections 4 to 8 cover the DNCA specifics, with + while Section 3 provides an introduction to DNCA and its overall + deployment framework. Sections 4 to 8 cover DNCA specifics, with Section 4 describing session management, Section 5 the use of the Diameter base protocol, Section 6 new commands, Section 7 AVPs used, and Section 8 accounting aspects. Section 9 presents an AVP occurance table. IANA and security considerations are addressed in Sections 10 and 11. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this @@ -224,22 +222,22 @@ NAPT: Network Address and Port Translation NAT: Network Address Translation (NAT and NAPT are used in this document interchangeably) NAT Binding or Binding: Association of two IP address/port pairs (with one IP address typically being private and the other one public) to facilitate NAT NAS: Network Access Server - NCR:NAT Control Request + NCR:NAT Control Request NCA:NAT Control Answer 3. Deployment Framework 3.1. Deployment Scenario Figure 1 shows a typical network deployment for Internet access. A user's IPv4 host gains access to the Internet though a NAS, which facilitates the authentication of the endpoint and configures the user's connection according to the authorization and configuration @@ -291,26 +289,26 @@ | | +--------+ +---------+ +---------+ +----------+ | IPv4/ | | | | | | IPv4 | | IPv6 |----| NAS |----| NAT |----| Internet | | Host | | | | | | | +--------+ +---------+ +---------+ +----------+ <-------- Private IPv4 -----------><--- Public IPv4 ---> <-------- Public IPv6 -----------><--- Public IPv4 ---> - Figure 2: Access network deployment with LSN + Figure 2: Access network deployment with NAT 3.2. Diameter NAPT Control Application Overview - The DNCA runs between a DNCA Agent on the NAT and the DNCA Manager. - DNCA allows per endpoint control and management of NAT. Based on + DNCA runs between a DNCA Agent on the NAT and DNCA Manager. DNCA + allows per endpoint control and management of NAT. Based on Diameter, DNCA integrates well with the suite of Diameter applications deployed for per endpoint authentication, authorization, accounting, and policy control in service provider networks. DNCA offers: o Request and answer commands to control the allowed number of NAT bindings per endpoint , to request the allocation of specific bindings for an endpoint, to define the address pool to be used for an endpoint. @@ -323,28 +321,28 @@ DNCA allows controlling the behavior of a NAT device on a per endpoint basis during initial session establishment and at later stages by providing an update procedure for already established sessions. Using DNCA, per endpoint NAT binding information can be retrieved either using accounting mechanisms or through an explicit session query to the NAT. 3.3. Deployment Scenarios For DNCA - The role of the Diameter NAT Control Manager can be fulfilled by - either the NAS or by an external server, such as AAA-server. The two - deployment scenarios are outlined in Figure 3 ("integrated - deployment") and Figure 4 ("autonomous deployment"). + The role of DNCA can be fulfilled by either the NAS or by an external + server, such as AAA-server. The two deployment scenarios are + outlined in Figure 3 ("integrated deployment") and Figure 4 + ("autonomous deployment"). Within the figures (M) denotes the network element, which takes on - the DNCA Manager role. Similarly, (A) identifies the network - element, which performs the DNCA Agent role. + DNCA Manager role. Similarly, (A) identifies the network element, + which performs DNCA Agent role. The integrated deployment approach hides the existence of the NAT device from external servers, such as the AAA-server as much as possible. It is suited for environments where minimal changes to the existing AAA deployment are desired. As DNCA Manager the NAS, initiates and manages session with the NAT device, exchanges NAT specific configuration information and handles reporting and accounting information. The NAS receives reporting and accounting information from NAT device. With this information, the NAS provides a single accounting record for the user. This reduces the usage of @@ -378,145 +376,144 @@ | | +--------+ +---------+ +---------+ +----------+ | IPv4/ | | (M) | | (A) | | IPv4 | | IPv6 |----| NAS |----| NAT |----| Internet | | Host | | | | | | | +--------+ +---------+ +---------+ +----------+ <-------- Public IPv6 ----------><--- Public IPv4 ----> <-------- Private IPv4 ----------><--- Public IPv4 ----> - Figure 3: LSN Control deployment: Integrated deployment + Figure 3: NAT Control deployment: Integrated deployment The autonomous deployment approach decouples user management on NAS - and NAT device. The AAA system performing the role of the DNCA - Manager manages the connection to the NAT device, controls the per - endpoint configuration, and also receives accounting and reporting - information from the NAT device. Different from the integrated - deployment scenario, the autonomous deployment scenario does not - "hide" the existence of the NAT device from the AAA infrastructure. - Here two accounting streams are received by the AAA-server for one - particular endpoint, one from the NAS, and one from the NAT device. + and NAT device. The AAA system performing the role of DNCA Manager + manages the connection to the NAT device, controls the per endpoint + configuration, and also receives accounting and reporting information + from the NAT device. Different from the integrated deployment + scenario, the autonomous deployment scenario does not "hide" the + existence of the NAT device from the AAA infrastructure. Here two + accounting streams are received by the AAA-server for one particular + endpoint, one from the NAS, and one from the NAT device. +---------+ | (M) | | AAA |--------- | | | +---------+ | | | | | | | +--------+ +---------+ +---------+ +----------+ | IPv4/ | | | | (A) | | IPv4 | | IPv6 |----| NAS |----| NAT |----| Internet | | Host | | | | | | | +--------+ +---------+ +---------+ +----------+ <-------- Public IPv6 ----------><---- Public IPv4 ---> <-------- Private IPv4 ----------><---- Public IPv4 ---> - Figure 4: LSN Control deployment: Autonomous deployment + Figure 4: NAT Control deployment: Autonomous deployment 4. DNCA Session Establishment and Management Note that this section forward references some of the commands and - AVPs defined for the DNCA. Please refer to Section 6 and Section 8 - for details. + AVPs defined for DNCA. Please refer to Section 6 and Section 8 for + details. 4.1. Parties Involved Authorization and control models supported by this application include the following parties: - o DNCA agent: The DNCA agent is part of the NAT device + o DNCA Agent: DNCA Agent is part of the NAT device o DNCA Manager - The NAT control requesting entity is always the DNCA Manager. The - DNCA Manager always initiates, updates, or terminates the sessions. - This mode of operation is sometimes also referred to as "push mode". + 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". - The DNCA Manager can be NAS or AAA-server. The DNCA Manager - initiates a session with the DNCA agent when it learns about the - subscriber. The 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. + 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 - The DNCA Manager establishes a session with the DNCA agent to control - the behavior of the NAT device. During session establishment, the - DNCA Manager passes along configuration information to the DNCA - agent. The session configuration information comprises the maximum - number of bindings allowed for the endpoint associated with this - session, a set of pre-defined NAT bindings to be established for this - endpoint, or a description of the address pool, external addresses to - be allocated from. + DNCA Manager establishes a session with DNCA Agent to control the + behavior of the NAT device. During session establishment, DNCA + Manager passes along configuration information to DNCA Agent. The + session configuration information comprises the maximum number of + bindings allowed for the endpoint associated with this session, a set + of pre-defined NAT bindings to be established for this endpoint, or a + description of the address pool, external addresses to be allocated + from. - The DNCA Manager initiates the Diameter NAT Control session to the - DNCA Agent. The DNCA Manager generates a NAT-Control Request (NCR) - message to the DNCA Agent with NC-Request-Type AVP set to - INITIAL_REQUEST. On receipt of NCR the DNCA Agent sets up a new - session for the endpoint associated with the endpoint classifier(s) - contained in the NCR. The DNCA agent notifies the DNCA Manager about - successful session setup using a NAT-Control Answer (NCA) message - with Result-Code set to DIAMETER_SUCCESS. Figure 5 shows the - protocol interaction between the DNCA Manager and the DNCA Agent. + DNCA Manager initiates the Diameter NAT Control session to DNCA + Agent. DNCA Manager generates a NAT-Control Request (NCR) message to + DNCA Agent with NC-Request-Type AVP set to INITIAL_REQUEST. On + receipt of NCR DNCA Agent sets up a new session for the endpoint + associated with the endpoint classifier(s) contained in the NCR. + DNCA Agent notifies DNCA Manager about successful session setup using + a NAT-Control Answer (NCA) message with Result-Code set to + DIAMETER_SUCCESS. Figure 5 shows the initial protocol interaction + between DNCA Manager and DNCA Agent. The initial NAT-Control-Request may contain configuration information for the session, which specifies the behavior of the NAT device for the session. The configuration information, which may be included, comprises: o A list of NAT bindings, which should be pre-allocated for the session; for example, in case a subscriber requires a fixed external IP- address/port pair for one of the applications. 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 session. - o A reference to a predefined binding rule on the DNCA Agent, which - is applied to the session. Such a predefined binding rule on the - DNCA Agent may contain, for example, the name of the IP address - pool that external IP addresses should be allocated from, maximum + o A reference to a predefined binding rule on DNCA Agent, which is + applied to the session. Such a predefined binding rule on DNCA + Agent may contain, for example, the name of the IP address pool + that external IP addresses should be allocated from, maximum number of bindings permitted for the endpoint etc. - In certain cases, the DNCA Agent may not be able to perform the tasks + In certain cases, DNCA Agent may not be able to perform the tasks requested within the NCR. These include the following: o If a DNCA Agent receives a NCR from a DNCA Manager with NC- Request-Type AVP set to INITIAL_REQUEST that identifies an already existing session; that is, DNCA Manager and endpoint identifier - match an already existing session, the DNCA Agent returns NCA with + match an already existing session, DNCA Agent returns NCA with Result-Code set to SESSION_EXISTS, and provides the Session-Id of the existing session in Duplicate-Session-Id AVP. o If a DNCA Agent receives an NCR from a DNCA Manager with NC- Request-Type AVP set to INITIAL_REQUEST that matches more than one of the already existing sessions; that is, DNCA Manager and - endpoint identifier match already existing sessions, the DNCA - Agent returns a NCA with Result-Code set to INSUFFICIENT- - CLASSIFIERS. In case a DNCA Manager receives NCA that reports - Insufficient-Classifiers, it may choose to retry establishing a - new session using additional and more specific classifiers. + endpoint identifier match already existing sessions, DNCA Agent + returns a NCA with Result-Code set to INSUFFICIENT-CLASSIFIERS. + In case a DNCA Manager receives NCA that reports Insufficient- + Classifiers, it may choose to retry establishing a new session + using additional and more specific classifiers. o If the NCR contains a binding rule not defined on the NAT device, - the DNCA Agent returns NCA with Result-Code AVP set to + DNCA Agent returns NCA with Result-Code AVP set to UNKNOWN_BINDING_RULE. - o In case the DNCA Agent is unable to establish all of the bindings + o In case DNCA Agent is unable to establish all of the bindings requested in the NCR, it will return a NCA with Result-Code set to - BINDING_FAILURE. The DNCA Agent, that is NAT device, treats a NCR - as an atomic operation; hence none of the requested bindings will - be established by the NAT device. Either all requested actions + BINDING_FAILURE. DNCA Agent, that is NAT device, treats a NCR as + an atomic operation; hence none of the requested bindings will be + established by the NAT device. Either all requested actions within a NCR are completed successfully, or the entire request fails. o If DNCA Agent does not have sufficient resources to process a request, it returns NCA with Result-Code set to RESOURCE_FAILURE. 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 predefined template on NAT device, and the values in Max-NAT- Binding and NAT-Control-Definition contradict those specified in @@ -541,83 +538,84 @@ | NCA | |<------------------------------------------| | (result code) | | | | | Figure 5: Initial NAT Control request and session establishment 4.3. Session Re-Authorization - Session re-authorization is performed if the DNCA Manager desires to + Session re-authorization is performed if DNCA Manager desires to 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. - The DNCA Manager generates a NCR message to the DNCA Agent with NC- - Request-Type AVP set to UPDATE_REQUEST upon receiving a trigger - signal. In case the session is updated successfully, the DNCA Agent - notifies the DNCA Manager about 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 DNCA Manager and the DNCA Agent. + DNCA Manager generates a NCR message to DNCA Agent with NC-Request- + Type AVP set to UPDATE_REQUEST upon receiving a trigger signal. In + case the session is updated successfully, DNCA Agent notifies DNCA + Manager about successful session update using a NAT-Control Answer + (NCA) message with Result-Code set to DIAMETER_SUCCESS. Figure 6 + shows the protocol interaction between DNCA Manager and DNCA Agent. - In certain cases, the DNCA Agent may not be able to perfborm the - tasks requested within the NCR. These include the following: + In certain cases, DNCA Agent may not be able to perform the tasks + requested within the NCR. These include the following: o If DNCA Agent receives a NCR update or query request for a non- existent session, it sets Result-Code in the answer to DIAMETER_UNKNOWN_SESSION_ID. o If the NCR contains a binding rule not defined on the NAT device, - the DNCA Agent returns NCA with Result-Code AVP set to + DNCA Agent returns NCA with Result-Code AVP set to UNKNOWN_BINDING_RULE. - o If the DNCA Agent cannot establish the requested binding because - the maximum number of allowed bindings has been reached for the + o If DNCA Agent cannot establish the requested binding because the + maximum number of allowed bindings has been reached for the Endpoint Classifier, it returns NCA with Result-Code AVP set to MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT. - o If the DNCA Agent cannot establish some or all of the bindings + o If DNCA Agent cannot establish some or all of the bindings requested in a NCR, but has not yet reached the maximum number of allowed bindings for the subscriber, it returns a NCA with Result- - Code set to BINDING_FAILURE. The DNCA Agent (i.e., NAT device) - treats a NCR as an atomic operation. Hence none of the requested + Code set to BINDING_FAILURE. DNCA Agent (i.e., NAT device) treats + a NCR as an atomic operation. Hence none of the requested bindings will be established by NAT device. Either all requested actions within a NCR are either successful or failed completely. o If DNCA Agent does not have sufficient resources to process a request, it returns NCA with Result-Code set to RESOURCE_FAILURE. o If a NCR redefines the maximum number of NAT bindings allowed for the endpoint, the new value will override any previously defined 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 value is lower than the actual number of allocated bindings. Typically the NAT device refrains from enforcing the new limit immediately; that is, actively remove bindings, but rather disallow the establishment of new bindings until the current number of bindings is lower than the newly established maximum number of allowed bindings. - o If a NCR specifies a new binding rule, predefined on the DNCA - agent, the binding rule overrides any previously defined rules for - the session. + o If a NCR specifies a new binding rule, predefined on DNCA Agent, + the binding rule overrides any previously defined rules for the + session. 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 template on NAT device) and the values in Max-NAT-Binding and NAT- Control-Definition AVPs contradict those specified in the pre- defined binding rule, Max-NAT-Binding and NAT-Control-Definition AVPs override the values specified in the binding rule. + Note: Already established bindings for the session will not be + affected. DNCA Manager DNCA Agent | | | | | | Change of session | attributes | | | | NCR | |------------------------------------------>| | (UPDATE_REQUEST session id, | @@ -630,57 +628,56 @@ | NCA | |<------------------------------------------| | (result code) | | | | | Figure 6: NAT Control request for session update 4.4. Session and Binding Query - Session query can be used by the DNCA Manager to either retrieve + Session query can be used by DNCA Manager to either retrieve information on the current bindings for a particular session at the NAT device or discover the session identifier for a particular external IP address/port pair. - The DNCA Manager initiates a session query by sending a NCR message - to the DNCA Agent with NC-Request-Type AVP set to QUERY_REQUEST. - Figure 7 shows the protocol interaction between the DNCA Manager and - the DNCA Agent. + DNCA Manager initiates a session query by sending a NCR message to + DNCA Agent with NC-Request-Type AVP set to QUERY_REQUEST. Figure 7 + shows the protocol interaction between DNCA Manager and DNCA Agent. 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 - the DNCA Manager retrieve the current set of bindings for a specific + DNCA Manager retrieve the current set of bindings for a specific session. The second type of query request is used to retrieve the session identifiers, along with the associated bindings, matching a - criteria. This enables the DNCA Manager to find the sessions, which + criteria. This enables DNCA Manager to find the sessions, which utilize a specific external IP address. 1. Request a list of currently allocated NAT bindings for a - particular session: The DNCA Agent on receiving NCR, looks up - session information for the session ID contained in the NCR, and - reports all currently active NAT bindings for the session using - NCA message with Result-Code set to DIAMETER_SUCCESS. In this - case the NCR MUST NOT contain a NAT-Control-Definition AVP. Each - NAT binding is reported in a NAT-Control-Definition AVP. In case - the session ID is unknown, the DNCA Agent returns NCA with - Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. + particular session: DNCA Agent on receiving NCR, looks up session + information for the session ID contained in the NCR, and reports + all currently active NAT bindings for the session using NCA + message with Result-Code set to DIAMETER_SUCCESS. In this case + the NCR MUST NOT contain a NAT-Control-Definition AVP. Each NAT + binding is reported in a NAT-Control-Definition AVP. In case the + session ID is unknown, DNCA Agent returns NCA with Result-Code + set to DIAMETER_UNKNOWN_SESSION_ID. 2. Retrieve session IDs and internal IP address/port pairs for one - or multiple external IP address/port pairs: If the DNCA Manager + or multiple external IP address/port pairs: If DNCA Manager wishes to retrieve the session ID(s) for one or multiple external IP address/port pairs, it MUST include the external IP address/ port pair(s) as part of the NAT-Control-Definition AVP of the NCR. The session ID is not included in the NCR or the NCA for - this type of a query. The DNCA Agent reports the NAT bindings - and associated session IDs corresponding to the external IP - address/port pairs in a NCA message with Result-Code set to + this type of a query. DNCA Agent reports the NAT bindings and + associated session IDs corresponding to the external IP address/ + port pairs in a NCA message with Result-Code set to DIAMETER_SUCCESS with the same session ID, which is used in NCR. 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. DNCA Manager DNCA Agent | | | | | | DNCA Session Established | @@ -697,31 +694,31 @@ | NCA | |<------------------------------------------| | (Result-Code) | | | | | Figure 7: Session Query 4.5. Session Termination - The DNCA Manager generates a Session Terminate Request (STR) message - to the DNCA Agent upon receiving a trigger signal. The source of the - trigger signal is outside the scope of this document. The DNCA Agent + DNCA Manager generates a Session Terminate Request (STR) message to + DNCA Agent upon receiving a trigger signal. The source of the + trigger signal is outside the scope of this document. DNCA Agent sends accounting stop record reporting all the bindings and notifies - the DNCA Manager about successful session termination using a Session + DNCA Manager about successful session termination using a Session Terminate Answer (STA) message with Result-Code set to DIAMETER_SUCCESS. Figure 8 shows the protocol interaction between - the DNCA Manager and the DNCA Agent. + DNCA Manager and DNCA Agent. If a DNCA Agent receives STR from a DNCA Manager and fails to find a - matching session, the DNCA Agent returns STA with Result-Code set to + matching session, DNCA Agent returns STA with Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. DNCA Manager DNCA Agent | | | | Trigger | | | | STR | |------------------------------------------->| | (session id) | @@ -743,141 +740,131 @@ | STA | |<-------------------------------------------| | (Result-Code) | | | Figure 8: Terminate NAT Control session 4.6. DNCA Manager and Agent Failures This document does not cover details in case DNCA Manager and DNCA - Agent are out of sync. This happens when the DNCA Manager or DNCA - Agent restart, (temporary) loss of network connectivity etc. The - DNCA relies on DNCA Manager and DNCA Agent to have builtin redundancy - support to recover state in case of failure. + Agent are out of sync. This happens when DNCA Manager or DNCA Agent + restart, (temporary) loss of network connectivity etc. DNCA Manager + and DNCA Agent MUST have builtin redundancy support to recover state + in case of failure. Example failure cases include the following: - o The DNCA Manager loses session state (e.g. due to a restart). In - this case, + o DNCA Manager loses session state (e.g. due to a restart). In this + case, - * The DNCA Agent may receive a NCR with NC-Request-Type AVP set - to INITIAL_REQUEST that matches an existing session of DNCA - agent. The DNCA Agent returns a Result-Code that contains - Duplicate-Session-Id AVP to report the Session-ID of existing - session. The DNCA Manager may send an explicit Sesstion - Terminate Request (STR) for the older session, which was lost. + * DNCA Agent may receive a NCR with NC-Request-Type AVP set to + INITIAL_REQUEST that matches an existing session of DNCA Agent. + DNCA Agent returns a Result-Code that contains Duplicate- + Session-Id AVP to report the Session-ID of existing session. + DNCA Manager may send an explicit Sesstion Terminate Request + (STR) for the older session, which was lost. - * The DNCA Manager may receive accounting records for a session - that does not exist. The DNCA Manager sends an accounting - answer with Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. On - receiving this, the DNCA Agent clears the session and removes - the associated session state. + * DNCA Manager may receive accounting records for a session that + does not exist. DNCA Manager sends an accounting answer with + Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. On receiving + this, DNCA Agent clears the session and removes the associated + session state. - o The DNCA Agent loses session state. In such a case, the DNCA - Agent may receive a NCR with NC-Request-Type AVP set to - UPDATE_REQUEST for a non-existent session. The DNCA Agent returns - NCA with Result-Code set to DIAMETER_UNKNOWN_SESSION_ID. + o DNCA Agent loses session state. In such a case, DNCA Agent may + receive a NCR with NC-Request-Type AVP set to UPDATE_REQUEST for a + non-existent session. DNCA Agent returns NCA with Result-Code set + to DIAMETER_UNKNOWN_SESSION_ID. - o The DNCA Manager is unreachable, for example detected by Diameter - watchdog, or down and accounting request from the DNCA Agent fails - to get a response. The mechanism to ensure that a DNCA Manager no + o DNCA Manager is unreachable, for example detected by Diameter + watchdog, or down and accounting request from DNCA Agent fails to + get a response. The mechanism to ensure that a DNCA Manager no longer has associated state for a session being cleared by a DNCA Agent is beyond the scope of this document. - o The DNCA Agent is unreachable or down and NCR requests fail to get - a response. Handling of this case depends on the actual service + o DNCA Agent is unreachable or down and NCR requests fail to get a + response. Handling of this case depends on the actual service offering of the service provider. The service provider can choose to terminate the access session to the endpoint. 5. Use Of The Diameter Base Protocol The Diameter Base Protocol defined by [RFC3588] applies with the clarifications listed in the present specification. 5.1. Securing Diameter Messages For secure transport of Diameter messages recommendations in [RFC3588] apply. - The DNCA Agent MAY verify the identity of the DNCA Manager during the + DNCA Agent MAY verify the identity of DNCA Manager during the Capabilities Exchange Request procedure. - The DNCA Agent MAY verify if the DNCA Manager that issues a NCR - command is allowed and it is based on: + DNCA Agent MAY verify if DNCA Manager that issues a NCR command is + allowed and it is based on: - o The identity of the DNCA Manager + o The identity of DNCA Manager o The type of NCR Command o The content of the NCR Command o Any combination of the above 5.2. Accounting Functionality Accounting functionality (accounting session state machine, related command codes and AVPs) is defined in Section 9 below. 5.3. Use Of Sessions 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 session. The Diameter Session-ID serves as the global endpoint - identifier. The DNCA Agent and DNCA Manager maintain state - associated with the Session-ID. This globally unique Session-ID is - used for updating, accounting, and terminating the session. The DNCA - session MUST NOT have more than one outstanding request at any given - instant. The DNCA Agent sends an Abort-Session-Request as defined in - [RFC3588] if it is unable to maintain sessions due to resource - limitation. + identifier. DNCA Agent and DNCA Manager maintain state associated + with the Session-ID. This globally unique Session-ID is used for + updating, accounting, and terminating the session. DNCA session MUST + NOT have more than one outstanding request at any given instant. + DNCA Agent sends an Abort-Session-Request as defined in [RFC3588] if + it is unable to maintain sessions due to resource limitation. 5.4. Routing Considerations - It is assumed that the DNCA Manager knows the DiameterIdentity of the - DNCA Agent for a given endpoint. Both the Destination-Realm and - Destination-Host AVPs are present in the request from the DNCA - Manager to the DNCA Agent. + It is assumed that DNCA Manager knows the DiameterIdentity of DNCA + Agent for a given endpoint. Both the Destination-Realm and + Destination-Host AVPs are present in the request from DNCA Manager to + DNCA Agent. 5.5. Advertising Application Support - Diameter applications conforming to this specification MUST advertise - support by including the value of TBD in: - - o Auth-Application-Id and Acct-Application-Id of Capabilities- - Exchange-Request (CER) - - o Auth-Application-Id of NC-request (NCR), NC-Answer (NCA), Abort- - Session-Request(ASR), Abort-Session-Answer (ASA) messages - - o Acct-Application-Id in Accounting-Request (ACR) and Accounting- - Answer (ACA) messages. + Diameter nodes conforming to this specification MUST advertise + support for DNCA by including the value of TBD in the Auth- + Application-Id of the Capabilities-Exchange-Request and Capabilities- + Exchange-Answer command[RFC3588]. 6. DNCA Commands The following commands are used to establish, maintain and query NAT bindings. 6.1. NAT-Control Request (NCR) Command 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 - from the DNCA Manager to the DNCA Agent in order to install NAT - bindings. + from DNCA Manager to DNCA Agent in order to install NAT bindings. User-Name, Logical-Access-Id, Physical-Access-ID, Framed-IP-Address, Framed-IPv6-Prefix , Framed-Interface-Id, EGRESS-VLANID, NAS-Port-ID, Address-Realm, Calling-Station-ID AVPs serve as identifiers for the subscriber. Message Format: - < NC-Request > ::= < Diameter Header: TBD, REQ, PXY> [ Session-Id ] { Auth-Application-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Destination-Host } { NC-Request-Type } [ Origin-State-Id ] *1 [ NAT-Control-Remove ] @@ -893,24 +880,23 @@ [ Address-Realm ] [ Calling-Station-ID ] * [ Proxy-Info ] * [ Route-Record ] * [ AVP ] 6.2. NAT-Control Answer (NCA) Command 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, - is sent by the DNCA Agent in response to NAT-Control-Request command. + is sent by DNCA Agent in response to NAT-Control-Request command. Message Format: - ::= < Diameter Header: TBD, PXY > [ Session-Id ] { Origin-Host } { Origin-Realm } { NC-Request-Type } [ Result-Code ] * [ NAT-Control-Definition ] [ Current-NAT-Bindings ] [ Origin-State-Id ] [ Error-Message ] @@ -924,43 +910,42 @@ * [ Proxy-Info ] * [ Route-Record ] * [ Failed-AVP ] * [ AVP ] * [ AVP ] 7. NAT Control Application Session State Machine This section contains a set of finite state machines, representing the life cycle of DNCA session, which MUST be observed by all - implementations of the DNCA Diameter application. DNCA Agent and - Manager are stateful and the state machine maintained is similar to - the stateful Client and Server authorization state machine described - in RFC3588. When a session is moved to the Idle state, any resources + implementations of DNCA Diameter application. DNCA Agent and Manager + are stateful and the state machine maintained is similar to the + stateful Client and Server authorization state machine described in + [RFC3588]. When a session is moved to the Idle state, any resources that were allocated for the particular session must be released. Any event not listed in the state machines MUST be considered as an error condition, and an answer, if applicable, MUST be returned to the originator of the message. - In the state table, the event 'Failure to send NCR' means that the - DNCA Manager is unable to send command NCR to the desired - destination. This could be due to the peer being down, or due to the - peer sending back a transient failure or temporary protocol error - notification DIAMETER_TOO_BUSY or DIAMETER_LOOP_DETECTED in the - Result-Code AVP of NCA. + In the state table, the event 'Failure to send NCR' means that DNCA + Manager is unable to send command NCR to the desired destination. + This could be due to the peer being down, or due to the peer sending + back a transient failure or temporary protocol error notification + DIAMETER_TOO_BUSY or DIAMETER_LOOP_DETECTED in the Result-Code AVP of + NCA. - In the state table "FAILED NCA" means that the DNCA Agent was not - able to honor corresponding NCR. This can happen due to any of the - transient and permanent error at DNCA Agent indicated by the - following error Result-Code values - RESOURCE_FAILURE, - UNKNOWN_BINDING_RULE_NAME, BINDING_FAILURE, - MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT, SESSION_EXISTS, - INSUFFICIENT_CLASSIFIERS + In the state table "FAILED NCA" means that DNCA Agent was not able to + honor corresponding NCR. This can happen due to any of the transient + and permanent error at DNCA Agent indicated by the following error + Result-Code values - RESOURCE_FAILURE, 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: MANAGER State Event Action New State ------------------------------------------------------------- Idle New Host detected that Send Pending requires NAT Control NCR Initial Request @@ -1106,62 +1092,60 @@ Result-Code AVP values that fall within the transient failures 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 able to be satisfied in the future. The following new values of the Result-Code AVP are defined: RESOURCE_FAILURE (TBD) - The DNCA Agent indicates that the binding could not be - installed or a new session could not be created due to resource - shortage. + DNCA Agent indicates that the binding could not be installed or + a new session could not be created due to resource shortage. 8.2.3. 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 should not be attempted again. The request may be able to be satisfied in the future. The following new values of the Result-Code AVP are defined: UNKNOWN_BINDING_RULE_NAME (TBD) - The DNCA Agent indicates that the binding could not be - installed or a new session could not be created due to resource - shortage. + DNCA Agent indicates that the binding could not be installed or + a new session could not be created due to resource shortage. BINDING_FAILURE (TBD) - The DNCA indicates that the requested binding(s) could not be + DNCA indicates that the requested binding(s) could not be installed. MAXIMUM_BINDINGS_REACHED_FOR_ENDPOINT (TBD) - The DNCA Agent denies the request because the maximum number of + DNCA Agent denies the request because the maximum number of allowed bindings has been reached for the specified Endpoint Classifier. SESSION_EXISTS (TBD) - The DNCA Agent denies request to initialize a new session, if - it already has a DNCA session that uses the same set of + DNCA Agent denies request to initialize a new session, if it + already has a DNCA session that uses the same set of classifiers as indicated by DNCA Manager in the new session initialization request. INSUFFICIENT_CLASSIFIERS (TBD) - The DNCA Agent defines request to initialize a new session, if - the classifiers in the request match more than one of the - existing sessions on DNCA Agent. + DNCA Agent defines request to initialize a new session, if the + classifiers in the request match more than one of the existing + sessions on DNCA Agent. 8.3. Reused NASREQ Diameter Application AVPs The following AVPs are reused from Diameter Network Access Server Application [RFC4005]. +---------------------+ | AVP Flag rules | +------------------+------+------------|----+-----+----+-----|----+ | | AVP | | | |SHLD| MUST| | | Attribute Name | Code | Value Type|MUST| MAY | NOT| NOT|Encr| @@ -1282,34 +1266,34 @@ 8.7.1. NC-Request-Type AVP The NC-Request-Type AVP (AVP Code TBD) is of type Enumerated and contains the reason for sending the NAT-Control-Request command. It shall be present in all NAT-Control-Request messages. The following values are defined: INITIAL_REQUEST (1) - An Initial Request is used to install binding at the DNCA Agent - on a successful access session setup. + An Initial Request is used to install binding at DNCA Agent on + a successful access session setup. UPDATE_REQUEST (2) An Update Request is used to update bindings previously installed on a given access session, to add new binding on a given access session, or to remove one or several binding(s) activated on a given access session. QUERY_REQUEST (4) - Query Request is used to query the DNCA Agent about the - currently installed bindings for an endpoint classifier. + Query Request is used to query DNCA Agent about the currently + installed bindings for an endpoint classifier. 8.7.2. NAT-Control-Install AVP 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- Bindings that defines maximum number of NAT bindings to be allowed for a subscriber and NAT-Control-Binding-Rule that references predefined policy template on DNCA Agent that may contain static bindings, maximum number of bindings to be allowed, address pool from which external binding address should be allocated. @@ -1331,21 +1315,21 @@ * [ NAT-Control-Definition ] [ NAT-Control-Binding-Rule ] * [ AVP ] 8.7.4. NAT-Control-Definition AVP The NAT-Control-Definition AVP (AVP code TBD) is of type Grouped, and it describes a binding. The NAT-Control-Definition AVP uniquely identifies the binding - between the DNCA Agent and the DNCA Manager. + between DNCA Agent and DNCA Manager. If both the NAT-Internal-Address and NAT-External-Address AVP(s) are supplied, it is a pre-defined binding. The Protocol AVP describes the transport protocol for the binding. The NAT-Control-Definition AVP can contain either zero or one Protocol AVP. If the Protocol AVP is omitted and if both internal and external address are specified then the binding reserves the addresses for all transport protocols. @@ -1413,56 +1397,55 @@ Control-Install AVPs of multiple subscribers. 8.7.9. Duplicate-Session-Id AVP 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 session. 9. Accounting Commands - The DNCA reuses session based accounting as defined in Diameter Base - Protocol,[RFC3588] to report the bindings per endpoint. This + DNCA reuses session based accounting as defined in Diameter Base + Protocol[RFC3588] to report the bindings per endpoint. This reporting is achieved by sending Diameter Accounting Requests (ACR) - [Start, Interim and Stop] from the DNCA Agent to DNCA Manager. + [Start, Interim and Stop] from DNCA Agent to DNCA Manager. - The DNCA Agent sends an ACR Start on receiving an NCR with NC- - Request-Type AVP set to INITIAL_REQUEST for a session or on creation - of the first binding for a session requested in an earlier NCR. The - DNCA may send ACR Interim updates, if required, either due to a - change in bindings resulting from a NCR with NC-Request-Type AVP set - to UPDATE_REQUEST, or periodically as specified in Acct-Interim- - Interval by the DNCA Manager, or when it creates or tears down - bindings. An ACR Stop is sent by the DNCA Agent on receiving STR. + DNCA Agent sends an ACR Start on receiving an NCR with NC-Request- + Type AVP set to INITIAL_REQUEST for a session or on creation of the + first binding for a session requested in an earlier NCR. DNCA may + send ACR Interim updates, if required, either due to a change in + bindings resulting from a NCR with NC-Request-Type AVP set to + UPDATE_REQUEST, or periodically as specified in Acct-Interim-Interval + by DNCA Manager, or when it creates or tears down bindings. An ACR + Stop is sent by DNCA Agent on receiving STR. The function of correlating the multiple bindings used by an endpoint at any given time is relegated to the post processor. - The DNCA Agent may trigger an interim accounting record when maximum + DNCA Agent may trigger an interim accounting record when maximum number of bindings, if received in NCR, is reached. 9.1. NAT Control Accounting Messages The ACR and ACA messages are reused as defined in Diameter Base Protocol [RFC3588] for exchanging endpoint NAT binding details - between the DNCA Agent and DNCA Manager. The DNCA Application ID is - used in the accounting commands. ACR contains one or more optional - NAT-Control-Record AVP to report the bindings. The DNCA Agent - indicates the number of allocated NAT bindings to the DNCA Manager - using the Current-NAT-Bindings AVP. This number needs to match the - number of bindings identified as active within the NAT-Control-Record - AVP. + between DNCA Agent and DNCA Manager. DNCA Application ID is used in + the accounting commands. ACR contains one or more optional NAT- + Control-Record AVP to report the bindings. DNCA Agent indicates the + number of allocated NAT bindings to DNCA Manager using the Current- + NAT-Bindings AVP. This number needs to match the number of bindings + identified as active within the NAT-Control-Record AVP. 9.2. NAT Control Accounting AVPs - In addition to AVPs for ACR specified in [RFC3588], the DNCA Agent - must add the NAT-Control-Record AVP. + In addition to AVPs for ACR specified in [RFC3588], DNCA Agent must + add the NAT-Control-Record AVP. 9.2.1. NAT-Control-Record 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 set to Created, Event-Timestamp indicates the binding creation time. If NAT-Control-Binding-Status is set to Removed, Event-Timestamp indicates the binding removal time. If NAT-Control-Binding-Status is active, Event-Timestamp need not be present; if a value is present, it indicates that binding is active at the given time. @@ -1514,58 +1496,58 @@ message. It is considered an error if there is more than one instance of the AVP. 1 One instance of the AVP MUST be present in the message. 1+ At least one instance of the AVP MUST be present in the message. 10.1. DNCA AVP Table for NAT Control Initial and Update Requests - The following table lists the DNCA specific AVPs that have to be - present in NCR and NCA with NC-Request-Type set to INITIAL_REQUEST or + The following table lists DNCA specific AVPs that have to be present + in NCR and NCA with NC-Request-Type set to INITIAL_REQUEST or UPDATE_REQUEST. +-------------------+ | Command Code | +-----------------------------------+-------------------+ | Attribute Name NCR NCA | +-------------------------------------------------------+ |NC-Request-Type 1 1 | |NAT-Control-Install 0-1 0 | |NAT-Control-Remove 0-1 0 | |NAT-Control-Definition 0 0 | |Current-NAT-Bindings 0 0 | |Duplicate-Session-Id 0 0-1 | +-------------------------------------------------------+ 10.2. DNCA AVP Table for Session Query request - The following table lists the DNCA specific AVPs that have to be - present in NCR and NCA with NC-Request-Type set to QUERY_REQUEST. + The following table lists DNCA specific AVPs that have to be present + in NCR and NCA with NC-Request-Type set to QUERY_REQUEST. +-------------------+ | Command Code | +-----------------------------------+-------------------+ | Attribute Name NCR NCA | +-------------------------------------------------------+ |NC-Request-Type 1 1 | |NAT-Control-Install 0 0 | |NAT-Control-Remove 0 0 | |NAT-Control-Definition 0 0+ | |Current-NAT-Bindings 0 1 | |Duplicate-Session-Id 0 0 | +-------------------------------------------------------+ 10.3. DNCA AVP Table for Accounting Message - The following table lists the DNCA specific AVPs, which may or may - not be present in ACR and ACA messages. + The following table lists DNCA specific AVPs, which may or may not be + present in ACR and ACA messages. +-------------------+ | Command Code | +-----------------------------------+-------------------+ | Attribute Name ACR ACA | +-------------------------------------------------------+ |NAT-Control-Record 0+ 0 | |Current-NAT-Bindings 1 0 | +-------------------------------------------------------+ 11. IANA Considerations @@ -1664,38 +1646,39 @@ Table 4: Diameter Application ID values 12. Security Considerations Similar to the impact of Diameter QoS application (see [RFC5866]) on authorization of QoS reservations, this document describes procedures for authorizing NAT related attributes and parameters by an entity, which is non-local to the device performing NAT. The security considerations for the Diameter QoS application (see [RFC5866] - section 11) apply in a similar way to the DNCA. Securing the - information exchange between the authorizing entity (the DNCA - Manager) and the NAT device requires bilateral authentication of the - involved parties, authorization of the involved parties to perform - the required procedures and functions, and procedures to ensure - integrity and confidentiality of the information exchange. The DNCA - makes use of the capabilities offered by Diameter and the underlying - transport protocols to deliver these requirements (see Section 5.1 ). + section 11) apply in a similar way to DNCA. To secure the + information exchange between the authorizing entity (DNCA Manager) + and the NAT device (DNCA Agent) requires bilateral authentication of + the involved parties, authorization of the involved parties to + 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 the DNCA Agent and DNCA Manager are in the same - domain and have a mutual trust set up. Authorization between the - DNCA Agent and DNCA Manager is beyond the scope of this document. + It is assumed that DNCA Agent and DNCA Manager are in the same domain + and have a mutual trust set up. Authorization between DNCA Agent and + DNCA Manager is beyond the scope of this document. 13. Acknowledgements The authors would like to thank Jouni Korhonen, Avi Lior, Chris Metz, - Hannes Tschofenig, Greg Weber, and Glen Zorn for their input on this - document. + Pallavi Mishra, Lionel Morand, 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) Changes from -00 to -01 a. new values for Result-Code AVP used - instead of Experimental- Result AVP b. added support for transport specific binding (UDP/TCP) @@ -1732,51 +1716,60 @@ multiple subscribers Changes from -04 to -05 a. Removed references to Large Scale NAT as per review comments Changes from -05 to -06 a. Editorial changes -15. References + Changes from -06 to -07 + a. Added a note in section 4.3 stating the state of pre-existing + bindings on update failure + + b. Security considerations are made consistent between sections 5.1 + and 12 + + c. Editorial changes + +15. References 15.1. Normative References [ETSIES283034] ETSI, "Telecommunications and Internet Converged Services and Protocols for Advanced Networks (TISPAN),Network Attachment Sub-System (NASS),e4 interface based on the Diameter protocol.", September 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. + [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, + "Diameter Network Access Server Application", RFC 4005, + August 2005. + [RFC4675] Congdon, P., Sanchez, M., and B. Aboba, "RADIUS Attributes for Virtual LAN and Priority Support", RFC 4675, September 2006. [RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M., and A. Lior, "Traffic Classification and Quality of Service (QoS) Attributes for Diameter", RFC 5777, February 2010. 15.2. Informative References - [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, - "Diameter Network Access Server Application", RFC 4005, - August 2005. - [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 Frank Brockners Cisco Hansaallee 249, 3rd Floor DUESSELDORF, NORDRHEIN-WESTFALEN 40549