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Versions: (draft-saintandre-sip-xmpp-chat) 00 01 02 03 04 05 06 07 08 09 10 11 RFC 7573

Network Working Group                                     P. Saint-Andre
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                               S. Loreto
Expires: January 2, 2014                                       E. Gavita
                                                              N. Hossain
                                                                Ericsson
                                                            July 1, 2013


   Interworking between the Session Initiation Protocol (SIP) and the
Extensible Messaging and Presence Protocol (XMPP): One-to-One Text Chat
                        draft-ietf-stox-chat-00

Abstract

   This document defines a bidirectional protocol mapping for the
   exchange of instant messages in the context of a one-to-one chat
   session between a user of the Session Initiation Protocol (SIP) and a
   user of the Extensible Messaging and Presence Protocol (XMPP).
   Specifically for SIP text chat, this document specifies a mapping to
   the Message Session Relay Protocol (MSRP).

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   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 January 2, 2014.

Copyright Notice

   Copyright (c) 2013 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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   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 . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  XMPP to MSRP . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  MSRP to XMPP . . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Appendix A.  Acknowledgements  . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12































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1.  Introduction

   Both the Session Initiation Protocol [RFC3261] and the Extensible
   Messaging and Presence Protocol [RFC6120] can be used for the purpose
   of one-to-one text chat over the Internet.  To ensure interworking
   between these technologies, it is important to define bidirectional
   protocol mappings.

   The architectural assumptions underlying such protocol mappings are
   provided in [I-D.ietf-stox-core], including mapping of addresses and
   error conditions.  This document specifies mappings for one-to-one
   text chat sessions (sometimes called "session-mode" messaging); in
   particular, this document specifies mappings between XMPP messages of
   type "chat" and the Message Session Relay Protocol [RFC4975].
   Mappings for single instant messages and groupchat are provided in
   separate documents.

   The approach taken here is to directly map syntax and semantics from
   one protocol to another.  The mapping described herein depends on the
   protocols defined in the following specifications:

   o  XMPP chat sessions using message stanzas of type "chat" are
      specified in [RFC6121].
   o  SIP-based chat sessions using the SIP INVITE and SEND request
      types are specified in [RFC4975].

   In SIMPLE, a chat session is formally negotiated just as any other
   session type is using SIP.  By contrast, a one-to-one chat "session"
   in XMPP is an informal construct and is not formally negotiated: a
   user simply sends a message of type "chat" to a contact, the contact
   then replies to the message, and the sum total of such messages
   exchanged during a defined period of time is considered to be a chat
   session.  To overcome the disparity between these approaches, a
   gateway that wishes to map between SIP and XMPP for one-to-one chat
   sessions needs to maintain some additional state, as described below.

   The discussion venue for this document is the mailing list of the
   STOX WG; visit https://www.ietf.org/mailman/listinfo/stox for
   subscription information and discussion archives.


2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].




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3.  XMPP to MSRP

   In XMPP, the "informal session" approach is to simply send someone a
   <message/> of type "chat" without starting any session negotiation
   ahead of time (as described in [RFC6121]).  The XMPP "informal
   session" approach maps very well into a SIP MESSAGE request, as
   described in [I-D.ietf-stox-core].  However, the XMPP informal
   session approach can also be mapped to MSRP if the XMPP-to-SIP
   gateway maintains additional state.

   The order of events is as follows.

   XMPP User                      GW                      SIP User
       |                          |                          |
       |(F1) (XMPP) Chat message  |                          |
       |------------------------->|                          |
       |                          |(F2) (SIP) INVITE         |
       |                          |------------------------->|
       |                          |(F3) (SIP) 200 OK         |
       |                          |<-------------------------|
       |                          |(F4) (SIP) ACK            |
       |                          |------------------------->|
       |                          |(F5) (MSRP) SEND          |
       |                          |------------------------->|
       |                          |(F6) (MSRP) A reply       |
       |                          |<-------------------------|
       |(F7) (XMPP) A reply       |                          |
       |<-------------------------|                          |
       |                          |                          |
       .                          .                          .
       .                          .                          .
       .                          .                          .
       |                          |                          |
       |                          |(F8) (SIP) BYE            |
       |                          |<-------------------------|
       |                          |(F9) (SIP) 200 OK         |
       |                          |------------------------->|
       |                          |                          |

   First the XMPP user would generate an XMPP chat message.











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   Example: (F1) Juliet sends an XMPP message

   <message from='juliet@example.com/balcony'
            to='romeo@example.net'
            type='chat'>
     <thread>711609sa</thread>
     <body>Art thou not Romeo, and a Montague?</body>
   </message>

   The local SIP-to-XMPP gateway at the SIMPLE server would then
   determine if Romeo supports MSRP.  If so, the SIP-to-XMPP gateway
   would initiate an MSRP session with Romeo on Juliet's behalf.

   Example: (F2) Gateway starts a formal session on behalf of Juliet

   INVITE sip:romeo@example.net SIP/2.0
   To: <sip:romeo@example.net>
   From: <sip:juliet@example.com>
   Contact: <sip:juliet@example.com>;gr=balcony
   Subject: Open chat with Juliet?
   Call-ID: 711609sa
   Content-Type: application/sdp

   c=IN IP4 x2s.example.com
   m=message 7654 TCP/MSRP *
   a=accept-types:text/plain
   a=lang:en
   a=lang:it
   a=path:msrp://x2s.example.com:7654/jshA7weztas;tcp

   Here we assume that Romeo accepts the MSRP session request.

   Example: (F3) Romeo accepts the request

   SIP/2.0 200 OK
   To: <sip:juliet@example.com>;gr=balcony
   From: <sip:romeo@example.net>
   Contact: <sip:romeo@example.net>;gr=orchard
   Call-ID: 711609sa
   Content-Type: application/sdp

   c=IN IP4 s2x.example.net
   m=message 12763 TCP/MSRP *
   a=accept-types:text/plain
   a=lang:it
   a=path:msrp://s2x.example.net:12763/kjhd37s2s20w2a;tcp

   The XMPP-to-SIP gateway then acknowledges the session acceptance on



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   behalf of Romeo.

   Example: (F4) Gateway sends ACK to Romeo's UA

   ACK sip:juliet@example.com SIP/2.0
   To: <sip:romeo@example.net>;gr=orchard
   From: <sip:juliet@example.com>
   Contact: <sip:juliet@example.com>;gr=balcony
   Call-ID: 711609sa

   The XMPP-to-SIP gateway then transforms the original XMPP chat
   message into MSRP.

   Example: (F5) Gateway transforms XMPP message to MSRP

   MSRP a786hjs2 SEND
   From-Path: msrp://x2s.example.com:7654/jshA7weztas;tcp
   To-Path: msrp://s2x.example.net:12763/kjhd37s2s20w2a;tcp
   Message-ID: 87652491
   Byte-Range: 1-25/25
   Content-Type: text/plain

   Art thou not Romeo, and a Montague?
   -------a786hjs2$

   Romeo can then send a reply using his MSRP user agent.

   Example: (F6) Romeo sends a reply

   MSRP a786hjs2 SEND
   To-Path: msrp://x2s.example.com:7654/jshA7weztas;tcp
   From-Path: msrp://s2x.example.net:12763/kjhd37s2s20w2a;tcp
   Message-ID: 87652491
   Byte-Range: 1-25/25
   Failure-Report: no
   Content-Type: text/plain

   Neither, fair saint, if either thee dislike.
   -------a786hjs2$

   The SIP-to-XMPP gateway would then transform that message into
   appropriate XMPP syntax for routing to the intended recipient.









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   Example: (F7) Gateway transforms MSRP message to XMPP

   <message from='romeo@example.net/orchard'
            to='juliet@example.com/balcony'
            type='chat'>
     <thread>711609sa</thread>
     <body>Neither, fair saint, if either thee dislike.</body>
   </message>

   When the MSRP user wishes to end the chat session, the user's MSRP
   client sends a SIP BYE.

   Example: (F8) Romeo terminates the chat session

   BYE juliet@example.com sip: SIP/2.0
   Max-Forwards: 70
   From: <sip:romeo@example.net>;tag=087js
   To: <sip:juliet@example.com>;tag=786
   Call-ID: 711609sa
   Cseq: 1 BYE
   Content-Length: 0

   The BYE is then acknowledged by the XMPP-to-SIP gateway.

   Example: (F9) Gateway acknowledges termination

   SIP/2.0 200 OK
   From: <sip:juliet@example.com>;tag=786
   To: <sip:romeo@example.net>;tag=087js
   Call-ID: 711609sa
   CSeq: 1 BYE
   Content-Length: 0


4.  MSRP to XMPP

   When an MSRP client sends messages through a gateway to an XMPP
   client that does not support formal sessinos, the order of events is
   as follows.












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   SIP User                     GW                     XMPP User
      |                         |                          |
      |(F1)(SIP) INVITE         |                          |
      |------------------------>|                          |
      |(F2)(SIP) 200 OK         |                          |
      |<------------------------|                          |
      |(F3)(SIP) ACK            |                          |
      |------------------------>|                          |
      |(F4)(MSRP) SEND          |                          |
      |------------------------>|                          |
      |                         |(F5)(XMPP) A chat message |
      |                         |------------------------->|
      |                         |(F6)(XMPP) A reply        |
      |                         |<-------------------------|
      |                         |                          |
      |(F7)(MSRP) SEND          |                          |
      |<------------------------|                          |
      |                         |                          |
      .                         .                          .
      .                         .                          .
      .                         .                          .
      |                         |                          |
      |(F8)(SIP) BYE            |                          |
      |------------------------>|                          |
      |(F9)(SIP) 200 OK         |                          |
      |<------------------------|                          |
      |                         |                          |

   Example: (F1) SIP user starts the session

   INVITE sip:juliet@example.com SIP/2.0
   To: <sip:juliet@example.com>
   From: <sip:romeo@example.net>
   Contact: <sip:romeo@example.net>;gr=orchard
   Subject: Open chat with Romeo?
   Call-ID: 742507no
   Content-Type: application/sdp

   c=IN IP4 s2x.example.net
   m=message 7313 TCP/MSRP *
   a=accept-types:text/plain
   a=lang:en
   a=lang:it
   a=path:msrp://s2x.example.net:7313/ansp71weztas;tcp







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   Example: (F2) Gateway accepts session on Juliet's behalf

   SIP/2.0 200 OK
   To: <sip:romeo@example.net>;gr=orchard
   From: <sip:juliet@example.com>
   Contact: <sip:juliet@example.com>;gr=balcony
   Call-ID: 742507no
   Content-Type: application/sdp

   c=IN IP4 x2s.example.com
   m=message 8763 TCP/MSRP *
   a=accept-types:text/plain
   a=lang:it
   a=path:msrp://x2s.example.com:8763/lkjh37s2s20w2a;tcp

   Example: (F3) Romeo sends ACK

   ACK sip:juliet@example.com SIP/2.0
   To: <sip:juliet@example.com>;gr=balcony
   From: <sip:romeo@example.net>
   Contact: <sip:romeo@example.net>;gr=orchard
   Call-ID: 742507no

   Example: (F4) Romeo sends a message

   MSRP ad49kswow SEND
   To-Path: msrp://x2s.example.com:8763/lkjh37s2s20w2a;tcp
   From-Path: msrp://s2x.example.net:7313/ansp71weztas;tcp
   Message-ID: 44921zaqwsx
   Byte-Range: 1-32/32
   Failure-Report: no
   Content-Type: text/plain

   I take thee at thy word ...
   -------ad49kswow$

   Example: (F5) Romeo sends a message (XMPP translation)

   <message from='romeo@example.net'
            to='juliet@example.com'
            type='chat'>
     <thread>742507no</thread>
     <body>I take thee at thy word ...</body>
   </message>







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   Example: (F6) Juliet sends a reply

   <message from='juliet@example.com'
            to='romeo@example.net'
            type='chat'>
     <thread>711609sa</thread>
     <body>What man art thou ...?</body>
   </message>

   Example: (F8) Gateway transforms XMPP message to MSRP

   MSRP a786hjs2 SEND
   To-Path: msrp://s2x.example.net:7313/jshA7weztas;tcp
   From-Path: msrp://x2s.example.com:8763/lkjh37s2s20w2a;tcp
   Message-ID: 87652491
   Byte-Range: 1-25/25
   Failure-Report: no
   Content-Type: text/plain

   What man art thou ...?
   -------a786hjs2$

   Example: (F9) Romeo terminates the session

   BYE juliet@example.com sip: SIP/2.0
   Max-Forwards: 70
   To: <sip:juliet@example.com>;gr=balcony
   From: <sip:romeo@example.net>
   Contact: <sip:romeo@example.net>;gr=orchard
   Call-ID: 742507no
   Cseq: 1 BYE
   Content-Length: 0

   Example: (F10) Gateway acknowledges the termination of the session on
   behalf of XMPP user

   SIP/2.0 200 OK
   To: <sip:juliet@example.com>;gr=balcony
   From: <sip:romeo@example.net>
   Contact: <sip:romeo@example.net>;gr=orchard
   Call-ID: 742507no
   CSeq: 1 BYE


5.  Security Considerations

   Detailed security considerations for instant messaging protocols are
   given in [RFC2779], for SIP-based instant messaging in [RFC3428] (see



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   also [RFC3261]), and for XMPP-based instant messaging in [RFC6121]
   (see also [RFC6120]).

   This document specifies methods for exchanging instant messages
   through a gateway that translates between SIP and XMPP.  Such a
   gateway MUST be compliant with the minimum security requirements of
   the instant messaging protocols for which it translates (i.e., SIP
   and XMPP).  The addition of gateways to the security model of instant
   messaging specified in [RFC2779] introduces some new risks.  In
   particular, end-to-end security properties (especially
   confidentiality and integrity) between instant messaging user agents
   that interface through a SIMPLE-XMPP gateway can be provided only if
   common formats are supported.  Specification of those common formats
   is out of scope for this document, although it is recommended to use
   [RFC3862] for instant messages.


6.  IANA Considerations

   This document requests no actions of IANA.


7.  References

7.1.  Normative References

   [I-D.ietf-stox-core]
              Saint-Andre, P., Houri, A., and J. Hildebrand,
              "Interworking between the Session Initiation Protocol
              (SIP) and the Extensible Messaging and Presence Protocol
              (XMPP): Core", draft-ietf-stox-core-00 (work in progress),
              July 2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

   [RFC3862]  Klyne, G. and D. Atkins, "Common Presence and Instant
              Messaging (CPIM): Message Format", RFC 3862, August 2004.

   [RFC4975]  Campbell, B., Mahy, R., and C. Jennings, "The Message
              Session Relay Protocol (MSRP)", RFC 4975, September 2007.

   [RFC6120]  Saint-Andre, P., "Extensible Messaging and Presence



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              Protocol (XMPP): Core", RFC 6120, March 2011.

   [RFC6121]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Instant Messaging and Presence",
              RFC 6121, March 2011.

7.2.  Informative References

   [RFC2779]  Day, M., Aggarwal, S., and J. Vincent, "Instant Messaging
              / Presence Protocol Requirements", RFC 2779,
              February 2000.

   [RFC3428]  Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
              and D. Gurle, "Session Initiation Protocol (SIP) Extension
              for Instant Messaging", RFC 3428, December 2002.


Appendix A.  Acknowledgements

   Some text in this document was borrowed from [I-D.ietf-stox-core].

   Thanks to Adrian Georgescu, Saul Ibarra, and Tory Patnoe for their
   feedback.


Authors' Addresses

   Peter Saint-Andre
   Cisco Systems, Inc.
   1899 Wynkoop Street, Suite 600
   Denver, CO  80202
   USA

   Phone: +1-303-308-3282
   Email: psaintan@cisco.com


   Salvatore Loreto
   Ericsson
   Hirsalantie 11
   Jorvas  02420
   Finland

   Email: Salvatore.Loreto@ericsson.com







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   Eddy Gavita
   Ericsson
   Decarie Boulevard
   Town of Mount Royal, Quebec
   Canada

   Email: eddy.gavita@ericsson.com


   Nazin Hossain
   Ericsson
   Decarie Boulevard
   Town of Mount Royal, Quebec
   Canada

   Email: Nazin.Hossain@ericsson.com



































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