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diff --git a/doc/rfc/rfc6737.txt b/doc/rfc/rfc6737.txt new file mode 100644 index 0000000..50aa33e --- /dev/null +++ b/doc/rfc/rfc6737.txt @@ -0,0 +1,339 @@ + + + + + + +Internet Engineering Task Force (IETF) K. Jiao +Request for Comments: 6737 Huawei +Category: Standards Track G. Zorn +ISSN: 2070-1721 Network Zen + October 2012 + + + The Diameter Capabilities Update Application + +Abstract + + This document defines a new Diameter application and associated + Command Codes. The Capabilities Update application is intended to + allow the dynamic update of certain Diameter peer capabilities while + the peer-to-peer connection is in the open state. + +Status of This Memo + + This is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6737. + +Copyright Notice + + Copyright (c) 2012 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 + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + + + + + + + +Jiao & Zorn Standards Track [Page 1] + +RFC 6737 Diameter Capabilities Update October 2012 + + +Table of Contents + + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 + 2. Specification of Requirements . . . . . . . . . . . . . . . . . 2 + 3. Diameter Protocol Considerations . . . . . . . . . . . . . . . 3 + 4. Capabilities Update . . . . . . . . . . . . . . . . . . . . . . 3 + 4.1. Command Code Values . . . . . . . . . . . . . . . . . . . . 4 + 4.1.1. Capabilities-Update-Request . . . . . . . . . . . . . . 4 + 4.1.2. Capabilities-Update-Answer . . . . . . . . . . . . . . 5 + 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 + 6.1. Application Identifier . . . . . . . . . . . . . . . . . . 5 + 6.2. Command Codes . . . . . . . . . . . . . . . . . . . . . . . 5 + 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 + 9.2. Informative References . . . . . . . . . . . . . . . . . . 6 + +1. Introduction + + Capabilities exchange is an important component of the Diameter base + protocol [RFC6733], allowing peers to exchange identities and + Diameter capabilities (protocol version number, supported Diameter + applications, security mechanisms, etc.). As defined in RFC 3588, + however, the capabilities exchange process takes place only once, at + the inception of a transport connection between a given pair of + peers. Therefore, if a peer's capabilities change (due to a software + update, for example), the existing connection(s) must be torn down + (along with all of the associated user sessions) and restarted before + the modified capabilities can be advertised. + + This document defines a new Diameter application intended to allow + the dynamic update of a subset of Diameter peer capabilities over an + existing connection. Because the Capabilities Update application + specified herein operates over an existing transport connection, + modification of certain capabilities is prohibited. Specifically, + modifying the security mechanism in use is not allowed; if the + security method used between a pair of peers is changed, the affected + connection MUST be restarted. + +2. Specification of Requirements + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in RFC 2119 [RFC2119]. + + + + + +Jiao & Zorn Standards Track [Page 2] + +RFC 6737 Diameter Capabilities Update October 2012 + + +3. Diameter Protocol Considerations + + This section details the relationship of the Diameter Capabilities + Update application to the Diameter base protocol. + + This document specifies Diameter Application-Id 10. Diameter nodes + conforming to this specification MUST advertise support by including + the value 10 in the Auth-Application-Id of the Capabilities-Exchange- + Request (CER) and Capabilities-Exchange-Answer (CEA) commands + [RFC6733]. + +4. Capabilities Update + + When the capabilities of a Diameter node conforming to this + specification change, the node MUST notify all of the nodes with + which it has an open transport connection and which have also + advertised support for the Capabilities Update application using the + Capabilities-Update-Request (CUR) message (Section 4.1.1). This + message allows the update of a peer's capabilities (supported + Diameter applications, etc.). + + A Diameter node only issues a given command to those peers that have + advertised support for the Diameter application that defines the + command; a Diameter node must cache the supported applications in + order to ensure that unrecognized commands and/or Attribute-Value + Pairs (AVPs) are not unnecessarily sent to a peer. + + The receiver of the CUR MUST determine common applications by + computing the intersection of its own set of supported Application + Ids against all of the Application-Id AVPs (Auth-Application-Id, + Acct-Application-Id, and Vendor-Specific-Application-Id) present in + the CUR. The value of the Vendor-Id AVP in the Vendor-Specific- + Application-Id MUST NOT be used during computation. + + If the receiver of a CUR does not have any applications in common + with the sender, then it MUST return a Capabilities-Update-Answer + (CUA) (Section 4.1.2) with the Result-Code AVP set to + DIAMETER_NO_COMMON_APPLICATION [RFC6733], and it SHOULD disconnect + the transport-layer connection. However, if active sessions are + using the connection, peers MAY delay disconnection until the + sessions can be redirected or gracefully terminated. Note that + receiving a CUA from a peer advertising itself as a relay (see + [RFC6733], Section 2.4) MUST be interpreted as having common + applications with the peer. + + As for CER/CEA messages, the CUR and CUA messages MUST NOT be + proxied, redirected, or relayed. + + + + +Jiao & Zorn Standards Track [Page 3] + +RFC 6737 Diameter Capabilities Update October 2012 + + + Even though the CUR/CUA messages cannot be proxied, it is still + possible for an upstream agent to receive a message for which there + are no peers available to handle the application that corresponds to + the Command Code. This could happen if, for example, the peers are + too busy or down. In such instances, the 'E' bit MUST be set in the + answer message with the Result-Code AVP set to + DIAMETER_UNABLE_TO_DELIVER to inform the downstream peer to take + action (e.g., re-routing requests to an alternate peer). + +4.1. Command Code Values + + This section defines Command Code [RFC6733] values that MUST be + supported by all Diameter implementations conforming to this + specification. The following Command Codes are defined in this + document: Capabilities-Update-Request (CUR, Section 4.1.1), and + Capabilities-Update-Answer (CUA, Section 4.1.2). The Diameter + Command Code Format (CCF) ([RFC6733], Section 3.2) is used in the + definitions. + +4.1.1. Capabilities-Update-Request + + The Capabilities-Update-Request (CUR), indicated by the Command Code + set to 328 and the Command Flags' 'R' bit set, is sent to update + local capabilities. Upon detection of a transport failure, this + message MUST NOT be sent to an alternate peer. + + When Diameter is run over the Stream Control Transmission Protocol + (SCTP) [RFC4960], which allows connections to span multiple + interfaces and multiple IP addresses, the Capabilities-Update-Request + message MUST contain one Host-IP-Address AVP for each potential IP + address that may be locally used when transmitting Diameter messages. + + Message Format + + <CUR> ::= < Diameter Header: 328, REQ > + { Origin-Host } + { Origin-Realm } + 1* { Host-IP-Address } + { Vendor-Id } + { Product-Name } + [ Origin-State-Id ] + * [ Supported-Vendor-Id ] + * [ Auth-Application-Id ] + * [ Acct-Application-Id ] + * [ Vendor-Specific-Application-Id ] + [ Firmware-Revision ] + * [ AVP ] + + + + +Jiao & Zorn Standards Track [Page 4] + +RFC 6737 Diameter Capabilities Update October 2012 + + +4.1.2. Capabilities-Update-Answer + + The Capabilities-Update-Answer, indicated by the Command Code set to + 328 and the Command Flags' 'R' bit cleared, is sent in response to a + CUR message. + + Message Format + + <CUA> ::= < Diameter Header: 328 > + { Origin-Host } + { Origin-Realm } + { Result-Code } + [ Error-Message ] + * [ AVP ] + +5. Security Considerations + + The security considerations applicable to the Diameter base protocol + [RFC6733] are also applicable to this document. + +6. IANA Considerations + + This section explains the criteria to be used by the IANA for + assignment of numbers within namespaces used within this document. + +6.1. Application Identifier + + This specification assigns the value 10 (Diameter Capabilities + Update) from the Application Identifiers namespace [RFC6733]. See + Section 3 for the assignment of the namespace in this specification. + +6.2. Command Codes + + This specification assigns the value 328 (Capabilities-Update- + Request/Capabilities-Update-Answer (CUR/CUA)) from the Command Codes + namespace [RFC6733]. See Section 4.1 for the assignment of the + namespace in this specification. + +7. Contributors + + This document is based upon work done by Tina Tsou. + +8. Acknowledgements + + Thanks to Sebastien Decugis, Niklas Neumann, Subash Comerica, Lionel + Morand, Dan Romascanu, Dan Harkins, and Ravi for helpful review and + discussion. + + + + +Jiao & Zorn Standards Track [Page 5] + +RFC 6737 Diameter Capabilities Update October 2012 + + +9. References + +9.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn, + "Diameter Base Protocol", RFC 6733, October 2012. + +9.2. Informative References + + [RFC4960] Stewart, R., "Stream Control Transmission Protocol", + RFC 4960, September 2007. + +Authors' Addresses + + Jiao Kang + Huawei Technologies + Section F1, Huawei Industrial Base + Bantian, Longgang District + Shenzhen 518129 + P.R. China + + EMail: kangjiao@huawei.com + + + Glen Zorn + Network Zen + 227/358 Thanon Sanphawut + Bang Na, Bangkok 10260 + Thailand + + Phone: +66 (0) 909-201060 + EMail: glenzorn@gmail.com + + + + + + + + + + + + + + + + +Jiao & Zorn Standards Track [Page 6] + |