Diameter Straightforward-Naming Authority Pointer (S-NAPTR) Usage
RFC 6408

Internet Engineering Task Force (IETF)                          M. Jones
Request for Comments: 6408                           Bridgewater Systems
Updates: 3588                                                J. Korhonen
Category: Standards Track                         Nokia Siemens Networks
ISSN: 2070-1721                                                L. Morand
                                                             Orange Labs
                                                           November 2011

   Diameter Straightforward-Naming Authority Pointer (S-NAPTR) Usage

Abstract

   The Diameter base protocol specifies mechanisms whereby a given realm
   may advertise Diameter nodes and the supported transport protocol.
   However, these mechanisms do not reveal the Diameter applications
   that each node supports.  A peer outside the realm would have to
   perform a Diameter capability exchange with every node until it
   discovers one that supports the required application.  This document
   updates RFC 3588, "Diameter Base Protocol", and describes an
   improvement using an extended format for the Straightforward-Naming
   Authority Pointer (S-NAPTR) application service tag that allows for
   discovery of the supported applications without doing Diameter
   capability exchange beforehand.

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/rfc6408.

Jones, et al.                Standards Track                    [Page 1]
RFC 6408                 Diameter S-NAPTR Usage            November 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
   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.

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................3
      2.1. Requirements Language ......................................3
   3. Extended NAPTR Service Field Format .............................3
      3.1. IETF Standards Track Diameter Applications .................5
      3.2. Vendor-Specific Diameter Applications ......................5
   4. Backwards Compatibility .........................................5
   5. Extended NAPTR-Based Diameter Peer Discovery ....................6
      5.1. Examples ...................................................7
   6. Usage Guidelines ................................................8
   7. IANA Considerations .............................................9
      7.1. IETF Diameter Application Service Tags .....................9
      7.2. 3GPP Diameter Application Service Tags .....................9
      7.3. WiMAX Forum Diameter Application Service Tags .............10
      7.4. Vendor-Specific Diameter Application Service Tags .........10
      7.5. Diameter Application Protocol Tags ........................11
   8. Security Considerations ........................................11
   9. Acknowledgments ................................................11
   10. References ....................................................12
      10.1. Normative References .....................................12
      10.2. Informative References ...................................14

1.  Introduction

   The Diameter base protocol [RFC3588] specifies three mechanisms for
   Diameter peer discovery.  One of these involves the Diameter
   implementation performing a Naming Authority Pointer (NAPTR) query
   [RFC3403] for a server in a particular realm.  These NAPTR records

Jones, et al.                Standards Track                    [Page 2]
RFC 6408                 Diameter S-NAPTR Usage            November 2011

   provide a mapping from a domain to the DNS Service Locator (SRV)