Diameter Applications Design Guidelines
RFC 7423

Internet Engineering Task Force (IETF)                    L. Morand, Ed.
Request for Comments: 7423                                   Orange Labs
BCP: 193                                                      V. Fajardo
Category: Best Current Practice                           Fluke Networks
ISSN: 2070-1721                                            H. Tschofenig
                                                           November 2014

                Diameter Applications Design Guidelines

Abstract

   The Diameter base protocol provides facilities for protocol
   extensibility enabling the definition of new Diameter applications or
   modification of existing applications.  This document is a companion
   document to the Diameter base protocol that further explains and
   clarifies the rules to extend Diameter.  Furthermore, this document
   provides guidelines to Diameter application designers reusing/
   defining Diameter applications or creating generic Diameter
   extensions.

Status of This Memo

   This memo documents an Internet Best Current Practice.

   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
   BCPs 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/rfc7423.

Morand, et al.            Best Current Practice                 [Page 1]
RFC 7423         Diameter Applications Design Guidelines   November 2014

Copyright Notice

   Copyright (c) 2014 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
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   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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Morand, et al.            Best Current Practice                 [Page 2]
RFC 7423         Diameter Applications Design Guidelines   November 2014

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Reusing Existing Diameter Applications  . . . . . . . . . . .   6
     4.1.  Adding a New Command  . . . . . . . . . . . . . . . . . .   7
     4.2.  Deleting an Existing Command  . . . . . . . . . . . . . .   8
     4.3.  Reusing Existing Commands . . . . . . . . . . . . . . . .   8
       4.3.1.  Adding AVPs to a Command  . . . . . . . . . . . . . .   8
       4.3.2.  Deleting AVPs from a Command  . . . . . . . . . . . .  10
       4.3.3.  Changing the Flag Settings of AVP in Existing
               Commands  . . . . . . . . . . . . . . . . . . . . . .  11
     4.4.  Reusing Existing AVPs . . . . . . . . . . . . . . . . . .  11
       4.4.1.  Setting of the AVP Flags  . . . . . . . . . . . . . .  11
       4.4.2.  Reuse of AVP of Type Enumerated . . . . . . . . . . .  12
   5.  Defining New Diameter Applications  . . . . . . . . . . . . .  12
     5.1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .  12
     5.2.  Defining New Commands . . . . . . . . . . . . . . . . . .  12
     5.3.  Use of Application Id in a Message  . . . . . . . . . . .  13
     5.4.  Application-Specific Session State Machines . . . . . . .  14
     5.5.  Session-Id AVP and Session Management . . . . . . . . . .  14
     5.6.  Use of Enumerated Type AVPs . . . . . . . . . . . . . . .  15