Internet DRAFT - draft-saintandre-sip-xmpp-chat
draft-saintandre-sip-xmpp-chat
Network Working Group P. Saint-Andre
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track S. Loreto
Expires: December 15, 2013 E. Gavita
N. Hossain
Ericsson
June 13, 2013
Interworking between the Session Initiation Protocol (SIP) and the
Extensible Messaging and Presence Protocol (XMPP): One-to-One Text Chat
draft-saintandre-sip-xmpp-chat-06
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 15, 2013.
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
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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.saintandre-sip-xmpp-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
DISPATCH WG; visit https://www.ietf.org/mailman/listinfo/dispatch 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.saintandre-sip-xmpp-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.saintandre-sip-xmpp-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-saintandre-sip-xmpp-core-05 (work in
progress), June 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.saintandre-sip-xmpp-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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