Network Working Group                                     H. Schulzrinne
Request for Comments: 4123                           Columbia University
Category: Informational                                         C. Agboh
                                                               July 2005


   Session Initiation Protocol (SIP)-H.323 Interworking Requirements

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

IESG Note

   This RFC is not a candidate for any level of Internet Standard.  The
   IETF disclaims any knowledge of the fitness of this RFC for any
   purpose, and in particular notes that the decision to publish is not
   based on IETF review for such things as security, congestion control,
   or inappropriate interaction with deployed protocols.  The RFC Editor
   has chosen to publish this document at its discretion.  Readers of
   this document should exercise caution in evaluating its value for
   implementation and deployment.  See [RFC3932] for more information.

Abstract

   This document describes the requirements for the logical entity known
   as the Session Initiation Protocol (SIP)-H.323 Interworking Function
   (SIP-H.323 IWF) that will allow the interworking between SIP and
   H.323.
















Schulzrinne & Agboh          Informational                      [Page 1]

RFC 4123                     SIP-H.323 Req.                    July 2005


Table of Contents

   1. Introduction ....................................................3
   2. Definitions .....................................................3
   3. Functionality within the SIP-H.323 IWF ..........................4
   4. Pre-Call Requirements ...........................................4
      4.1. Registration with H.323 Gatekeeper .........................5
      4.2. Registration with SIP Server ...............................5
   5. General Interworking Requirements ...............................5
      5.1. Basic Call Requirements ....................................5
           5.1.1. General Requirements ................................5
           5.1.2. Address Resolution ..................................6
           5.1.3. Call with H.323 Gatekeeper ..........................6
           5.1.4. Call with SIP Registrar .............................6
           5.1.5. Capability Negotiation ..............................6
           5.1.6. Opening of Logical Channels .........................7
      5.2. IWF H.323 Features .........................................7
      5.3. Overlapped Sending .........................................7
           5.3.1. DTMF Support ........................................7
   6. Transport .......................................................8
   7. Mapping between SIP and H.323 ...................................8
      7.1. General Requirements .......................................8
      7.2. H.225.0 and SIP Call Signaling .............................8
      7.3. Call Sequence ..............................................9
      7.4. State Machine Requirements .................................9
   8. Security Considerations ........................................10
   9. Examples and Scenarios .........................................10
      9.1. Introduction ..............................................10
      9.2. IWF Configurations ........................................11
      9.3. Call Flows ................................................11
           9.3.1. Call from H.323 Terminal to SIP UA .................11
           9.3.2. Call from SIP UA to H.323 Terminal .................12
   10. Acknowledgments ...............................................12
   11. Contributors ..................................................13
   12. References ....................................................14
       12.1. Normative References ....................................