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2 Network Working Group P. Saint-Andre
3 Internet-Draft &yet
4 Intended status: Standards Track A. Houri
5 Expires: September 12, 2014 IBM
6 J. Hildebrand
7 Cisco Systems, Inc.
8 March 11, 2014
10 Interworking between the Session Initiation Protocol (SIP) and the
11 Extensible Messaging and Presence Protocol (XMPP): Instant Messaging
12 draft-ietf-stox-im-08
14 Abstract
16 This document defines a bidirectional protocol mapping for the
17 exchange of single instant messages between the Session Initiation
18 Protocol (SIP) and the Extensible Messaging and Presence Protocol
19 (XMPP).
21 Status of This Memo
23 This Internet-Draft is submitted in full conformance with the
24 provisions of BCP 78 and BCP 79.
26 Internet-Drafts are working documents of the Internet Engineering
27 Task Force (IETF). Note that other groups may also distribute
28 working documents as Internet-Drafts. The list of current Internet-
29 Drafts is at http://datatracker.ietf.org/drafts/current/.
31 Internet-Drafts are draft documents valid for a maximum of six months
32 and may be updated, replaced, or obsoleted by other documents at any
33 time. It is inappropriate to use Internet-Drafts as reference
34 material or to cite them other than as "work in progress."
36 This Internet-Draft will expire on September 12, 2014.
38 Copyright Notice
40 Copyright (c) 2014 IETF Trust and the persons identified as the
41 document authors. All rights reserved.
43 This document is subject to BCP 78 and the IETF Trust's Legal
44 Provisions Relating to IETF Documents
45 (http://trustee.ietf.org/license-info) in effect on the date of
46 publication of this document. Please review these documents
47 carefully, as they describe your rights and restrictions with respect
48 to this document. Code Components extracted from this document must
49 include Simplified BSD License text as described in Section 4.e of
50 the Trust Legal Provisions and are provided without warranty as
51 described in the Simplified BSD License.
53 Table of Contents
55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
56 2. Intended Audience . . . . . . . . . . . . . . . . . . . . . . 3
57 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
58 4. XMPP to SIP . . . . . . . . . . . . . . . . . . . . . . . . . 3
59 5. SIP to XMPP . . . . . . . . . . . . . . . . . . . . . . . . . 6
60 6. Content Types . . . . . . . . . . . . . . . . . . . . . . . . 8
61 7. Internationalization Considerations . . . . . . . . . . . . . 8
62 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
63 9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
64 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
65 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11
66 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
68 1. Introduction
70 In order to help ensure interworking between instant messaging (IM)
71 systems that conform to the instant messaging / presence requirements
72 [RFC2779], it is important to clearly define protocol mappings
73 between such systems. Within the IETF, work has proceeded on two
74 instant messaging technologies:
76 o Various extensions to the Session Initiation Protocol ([RFC3261])
77 for instant messaging, in particular the MESSAGE method extension
78 [RFC3428]
80 o The Extensible Messaging and Presence Protocol (XMPP), which
81 consists of a formalization of the core XML streaming protocols
82 developed originally by the Jabber open-source community; the
83 relevant specifications are [RFC6120] for the XML streaming layer
84 and [RFC6121] for basic presence and instant messaging extensions
86 One approach to helping ensure interworking between these protocols
87 is to map each protocol to the abstract semantics described in
88 [RFC3860]; that is the approach taken by
89 [I-D.ietf-simple-cpim-mapping] and [RFC3922]. By contrast, the
90 approach taken in this document is to directly map semantics from one
91 protocol to another (i.e., from SIP/SIMPLE to XMPP and vice-versa).
93 Both XMPP and IM-capable SIP systems enable entities to exchange
94 "instant messages". The term "instant message" usually refers to a
95 message sent between two entities for delivery in close to real time
96 (rather than a message that is stored and forwarded to the intended
97 recipient upon request). This document covers single messages only
98 (sometimes called "pager-mode" messaging), since they form the lowest
99 common denominator for IM. Separate documents cover one-to-one chat
100 sessions [I-D.ietf-stox-chat] and multi-party groupchat
101 [I-D.ietf-stox-groupchat].
103 The architectural assumptions underlying such direct mappings are
104 provided in [I-D.ietf-stox-core], including mapping of addresses and
105 error conditions. The mappings specified in this document cover
106 basic instant messaging functionality, i.e., the exchange of a single
107 instant message between a SIP user and an XMPP user in either
108 direction. Mapping of more advanced functionality is out of scope
109 for this document, but other documents in this "series" cover such
110 topics.
112 2. Intended Audience
114 The documents in this series are intended for use by software
115 developers who have an existing system based on one of these
116 technologies (e.g., SIP), and would like to enable communication from
117 that existing system to systems based on the other technology (e.g.,
118 XMPP). We assume that readers are familiar with the core
119 specifications for both SIP [RFC3261] and XMPP [RFC6120], with the
120 base document for this series [I-D.ietf-stox-core], and with the
121 following IM-related specifications:
123 o Session Initiation Protocol (SIP) Extension for Instant Messaging
124 [RFC3428]
126 o Extensible Messaging and Presence Protocol: Instant Messaging and
127 Presence [RFC6121]
129 3. Terminology
131 A number of terms used here are explained in [RFC3261], [RFC3428],
132 [RFC6120], and [RFC6121].
134 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
135 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
136 "OPTIONAL" in this document are to be interpreted as described in
137 [RFC2119].
139 4. XMPP to SIP
141 As described in [RFC6121], a single instant message is an XML
142 stanza of type "normal" sent over an XML stream (since
143 "normal" is the default for the 'type' attribute of the
144 stanza, the attribute is often omitted). In this document we will
145 assume that such a message is sent from an XMPP client to an XMPP
146 server over an XML stream negotiated between the client and the
147 server, and that the client is controlled by a human user (this is a
148 simplifying assumption introduced for explanatory purposes only; the
149 XMPP sender could be an automated client, a component such as a
150 workflow application, a server, etc.).
152 When Juliet wants to send an instant message to Romeo, she interacts
153 with her XMPP client, which generates an XMPP stanza. The
154 syntax of the stanza, including required and optional
155 elements and attributes, is defined in [RFC6121] (for single instant
156 messages, the value of the 'to' address SHOULD be a "bare JID" of the
157 form "localpart@domainpart"). The following is an example of such a
158 stanza:
160 Example 1: XMPP user sends message
162 |
164 | Art thou not Romeo, and a Montague?
165 |
167 Upon receiving such a message stanza, the XMPP server needs to
168 determine the identity of the domainpart in the 'to' address, which
169 it does by following the procedures explained in Section 5 of
170 [I-D.ietf-stox-core]. If the domain is a SIP domain, the XMPP server
171 will hand off the message stanza to an XMPP-to-SIP gateway or
172 connection manager that natively communicates with IM-aware SIP
173 servers.
175 The XMPP-SIP gateway is then responsible for translating the XMPP
176 message stanza into a SIP MESSAGE request from the XMPP user to the
177 SIP user:
179 Example 2: XMPP user sends message (SIP transformation)
181 | MESSAGE sip:romeo@example.net SIP/2.0
182 | Via: SIP/2.0/TCP x2s.example.com;branch=z9hG4bK776sgdkse
183 | Max-Forwards: 70
184 | To: sip:romeo@example.net
185 | From: ;tag=12345
186 | Call-ID: D9AA95FD-2BD5-46E2-AF0F-6CFAA96BDDFA
187 | CSeq: 1 MESSAGE
188 | Content-Type: text/plain
189 | Content-Length: 35
190 |
191 | Art thou not Romeo, and a Montague?
192 The destination SIP server is responsible for delivering the message
193 to the intended recipient, and the recipient is responsible for
194 generating a response (e.g., 200 OK).
196 Example 3: SIP user agent indicates receipt of message
198 | SIP/2.0 200 OK
199 | Via: SIP/2.0/TCP x2s.example.com;branch=z9hG4bK776sgdkse
200 | From: sip:romeo@example.net;tag=vwxyz
201 | To: sip:juliet@example.com;tag=12345
202 | Call-ID: D9AA95FD-2BD5-46E2-AF0F-6CFAA96BDDFA
203 | CSeq: 1 MESSAGE
204 | Content-Length: 0
206 As described in [RFC3428], a downstream proxy could fork a MESSAGE
207 request, but it would return only one 200 OK to the gateway.
209 Informational Note: This document does not specify handling of the
210 200 OK by the XMPP-SIP gateway (e.g., to enable message
211 acknowledgements). See [I-D.ietf-stox-chat] for a mapping of
212 message acknowledgements in the context of one-to-one chat
213 sessions.
215 The mapping of XMPP syntax to SIP syntax SHOULD be as shown in the
216 following table. (Mappings for several aspects not mentioned here
217 are specified in [I-D.ietf-stox-chat].)
219 Table 1: Message syntax mapping from XMPP to SIP
221 +-----------------------------+--------------------------+
222 | XMPP Element or Attribute | SIP Header or Contents |
223 +-----------------------------+--------------------------+
224 | | body of MESSAGE |
225 | | Subject |
226 | | Call-ID |
227 | from | From (1) |
228 | id | (no mapping) |
229 | to | To or Request-URI |
230 | type | (no mapping) (2) |
231 | xml:lang | Content-Language |
232 +-----------------------------+--------------------------+
234 1. As shown in the foregoing example and described in
235 [I-D.ietf-stox-core], the XMPP-SIP gateway SHOULD map the full
236 JID (localpart@domainpart/resourcepart) of the XMPP sender to the
237 SIP From header and include the resourcepart as the GRUU portion
238 [RFC5627] of the SIP URI.
240 2. Because there is no SIP header field that matches the meaning of
241 the XMPP message 'type' values ("normal", "chat", "groupchat",
242 "headline", "error"), no general mapping is possible here.
244 5. SIP to XMPP
246 As described in [RFC3428], a single instant message is a SIP MESSAGE
247 request sent from a SIP user agent to an intended recipient who is
248 most generally referenced by an Instant Message URI of the form
249 but who might be referenced by a SIP or SIPS URI of
250 the form or . Here again we
251 introduce the simplifying assumption that the user agent is
252 controlled by a human user, whom we shall dub .
254 When Romeo wants to send an instant message to Juliet, he interacts
255 with his SIP user agent, which generates a SIP MESSAGE request. The
256 syntax of the MESSAGE request is defined in [RFC3428]. The following
257 is an example of such a request:
259 Example 4: SIP user sends message
261 | MESSAGE sip:juliet@example.com SIP/2.0
262 | Via: SIP/2.0/TCP s2x.example.net;branch=z9hG4bKeskdgs677
263 | Max-Forwards: 70
264 | To: sip:juliet@example.com
265 | From: sip:romeo@example.net;tag=vwxyz
266 | Call-ID: 9E97FB43-85F4-4A00-8751-1124FD4C7B2E
267 | CSeq: 1 MESSAGE
268 | Content-Type: text/plain
269 | Content-Length: 44
270 |
271 | Neither, fair saint, if either thee dislike.
273 Section 5 of [RFC3428] stipulates that a SIP User Agent presented
274 with an im: URI should resolve it to a sip: or sips: URI. Therefore
275 we assume that the Request-URI of a request received by an IM-capable
276 SIP-XMPP gateway will contain a sip: or sips: URI. Upon receiving
277 the MESSAGE, the SIP (MSRP) server needs to determine the identity of
278 the domain portion of the Request-URI or To header, which it does by
279 following the procedures explained in Section 5 of
280 [I-D.ietf-stox-core]. If the domain is an XMPP domain, the SIP
281 server will hand off the MESSAGE to an associated SIP-XMPP gateway or
282 connection manager that natively communicates with XMPP servers.
284 The SIP-to-XMPP gateway is then responsible for translating the
285 request into an XMPP message stanza from the SIP user to the XMPP
286 user and returning a SIP "200 OK" message to the sender:
288 Example 5: SIP user sends message (XMPP transformation)
290 |
292 | Neither, fair saint, if either thee dislike.
293 |
295 Note that the stanza handling rules specified in [RFC6121] allow the
296 receiving XMPP server to deliver a message stanza whose 'to' address
297 is a bare JID ("localpart@domainpart") to multiple connected devices.
298 This is similar to the "forking" of messages in SIP.
300 The mapping of SIP syntax to XMPP syntax SHOULD be as shown in the
301 following table. (Mappings for several aspects not mentioned here
302 are specified in [I-D.ietf-stox-chat].)
304 Table 2: Message syntax mapping from SIP to XMPP
306 +--------------------------+-----------------------------+
307 | SIP Header or Contents | XMPP Element or Attribute |
308 +--------------------------+-----------------------------+
309 | Call-ID | |
310 | Content-Language | xml:lang |
311 | CSeq | (no mapping) |
312 | From | from (1) |
313 | Subject | |
314 | Request-URI or To | to |
315 | body of MESSAGE | |
316 +--------------------------+-----------------------------+
318 1. As shown in the foregoing example and described in
319 [I-D.ietf-stox-core], if the IM-capable SIP-XMPP gateway has
320 information about the GRUU [RFC5627] of the particular endpoint
321 that sent the SIP message then it SHOULD map the sender's address
322 to a full JID (localpart@domainpart/resourcepart) in the 'from'
323 attribute of the XMPP stanza and include the GRUU as the
324 resourcepart.
326 When transforming SIP pager-mode messages, an IM-capable SIP-XMPP
327 gateway SHOULD specify no XMPP 'type' attribute or, equivalently, a
328 'type' attribute whose value is "normal" [RFC6121].
330 See Section 6 of this document about the handling of SIP message
331 bodies that contain content types other than plain text.
333 6. Content Types
335 SIP requests of type MESSAGE are allowed to contain essentially any
336 content type. The recommended procedures for SIP-to-XMPP gateways to
337 use in handling these content types are as follows.
339 An IM-aware SIP-to-XMPP gateway MUST process SIP messages that
340 contain message bodies of type "text/plain" and MUST encapsulate such
341 message bodies as the XML character data of the XMPP element.
343 An IM-aware SIP-to-XMPP gateway SHOULD process SIP messages that
344 contain message bodies of type "text/html"; if so, a gateway MUST
345 transform the "text/html" content into XHTML content that conforms to
346 the XHTML-IM Integration Set specified in [XEP-0071].
348 Although an IM-aware SIP-to-XMPP gateway MAY process SIP messages
349 that contain message bodies of types other than "text/plain" and
350 "text/html", the handling of such content types is a matter of
351 implementation.
353 7. Internationalization Considerations
355 Both XMPP and SIP support the UTF-8 encoding [RFC3629] of Unicode
356 characters [UNICODE] within messages, and signalling of the language
357 for a particular message (in XMPP via the 'xml:lang' attribute and in
358 SIP via the Content-Language header). Several examples follow, using
359 the "XML Notation" for Unicode characters outside the ASCII range
360 described in [RFC3987].
362 Example 6: SIP user sends message
364 | MESSAGE sip:juliet@example.com SIP/2.0
365 | Via: SIP/2.0/TCP s2x.example.net;branch=z9hG4bKeskdgs677
366 | Max-Forwards: 70
367 | To: sip:juliet@example.com
368 | From: sip:romeo@example.net;tag=vwxyz
369 | Call-ID: 9E97FB43-85F4-4A00-8751-1124FD4C7B2E
370 | CSeq: 1 MESSAGE
371 | Content-Type: text/plain
372 | Content-Length: 45
373 | Content-Language: cs
374 |
375 | Nic z ob쎩ho, m쎡 d쒛vo spanil쎡,
376 | nenavid쎭얡-li jedno nebo druh쎩.
378 Example 7: SIP user sends message (XMPP transformation)
380 |
383 |
384 | Nic z ob쎩ho, m쎡 d쒛vo spanil쎡,
385 | nenavid쎭얡-li jedno nebo druh쎩.
386 |
387 |
389 8. IANA Considerations
391 This document requests no actions of IANA.
393 9. Security Considerations
395 Detailed security considerations for instant messaging protocols are
396 given in [RFC2779], for SIP-based instant messaging in [RFC3428] (see
397 also [RFC3261]), and for XMPP-based instant messaging in [RFC6121]
398 (see also [RFC6120]). The security considerations provided in
399 [I-D.ietf-stox-core] also apply.
401 This document specifies methods for exchanging instant messages
402 through a gateway that translates between SIP and XMPP. Such a
403 gateway MUST be compliant with the minimum security requirements of
404 the instant messaging protocols for which it translates (i.e., SIP
405 and XMPP). The addition of gateways to the security model of instant
406 messaging specified in [RFC2779] introduces some new risks. In
407 particular, end-to-end security properties (especially
408 confidentiality and integrity) between instant messaging user agents
409 that interface through an IM-capable SIP-XMPP gateway can be provided
410 only if common formats are supported. Specification of those common
411 formats is out of scope for this document, although it is preferred
412 to use [RFC3862] for instant messages.
414 10. References
416 10.1. Normative References
418 [I-D.ietf-stox-chat]
419 Saint-Andre, P. and S. Loreto, "Interworking between the
420 Session Initiation Protocol (SIP) and the Extensible
421 Messaging and Presence Protocol (XMPP): One-to-One Text
422 Chat Sessions", draft-ietf-stox-chat-06 (work in
423 progress), March 2014.
425 [I-D.ietf-stox-core]
426 Saint-Andre, P., Houri, A., and J. Hildebrand,
427 "Interworking between the Session Initiation Protocol
428 (SIP) and the Extensible Messaging and Presence Protocol
429 (XMPP): Core", draft-ietf-stox-core-11 (work in progress),
430 February 2014.
432 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
433 Requirement Levels", BCP 14, RFC 2119, March 1997.
435 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
436 A., Peterson, J., Sparks, R., Handley, M., and E.
437 Schooler, "SIP: Session Initiation Protocol", RFC 3261,
438 June 2002.
440 [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
441 and D. Gurle, "Session Initiation Protocol (SIP) Extension
442 for Instant Messaging", RFC 3428, December 2002.
444 [RFC5627] Rosenberg, J., "Obtaining and Using Globally Routable User
445 Agent URIs (GRUUs) in the Session Initiation Protocol
446 (SIP)", RFC 5627, October 2009.
448 [RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
449 Protocol (XMPP): Core", RFC 6120, March 2011.
451 [RFC6121] Saint-Andre, P., "Extensible Messaging and Presence
452 Protocol (XMPP): Instant Messaging and Presence", RFC
453 6121, March 2011.
455 [XEP-0071]
456 Saint-Andre, P., "XHTML-IM", XSF XEP 0071, November 2012.
458 10.2. Informative References
460 [I-D.ietf-simple-cpim-mapping]
461 Rosenberg, J. and B. Campbell, "CPIM Mapping of SIMPLE
462 Presence and Instant Messaging", draft-ietf-simple-cpim-
463 mapping-01 (work in progress), June 2002.
465 [I-D.ietf-stox-groupchat]
466 Saint-Andre, P., Corretge, S., and S. Loreto,
467 "Interworking between the Session Initiation Protocol
468 (SIP) and the Extensible Messaging and Presence Protocol
469 (XMPP): Groupchat", draft-ietf-stox-groupchat-02 (work in
470 progress), December 2013.
472 [RFC2779] Day, M., Aggarwal, S., and J. Vincent, "Instant Messaging
473 / Presence Protocol Requirements", RFC 2779, February
474 2000.
476 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
477 10646", STD 63, RFC 3629, November 2003.
479 [RFC3860] Peterson, J., "Common Profile for Instant Messaging
480 (CPIM)", RFC 3860, August 2004.
482 [RFC3862] Klyne, G. and D. Atkins, "Common Presence and Instant
483 Messaging (CPIM): Message Format", RFC 3862, August 2004.
485 [RFC3922] Saint-Andre, P., "Mapping the Extensible Messaging and
486 Presence Protocol (XMPP) to Common Presence and Instant
487 Messaging (CPIM)", RFC 3922, October 2004.
489 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
490 Identifiers (IRIs)", RFC 3987, January 2005.
492 [UNICODE] The Unicode Consortium, "The Unicode Standard, Version
493 6.3", 2013,
494 .
496 Appendix A. Acknowledgements
498 The authors wish to thank the following individuals for their
499 feedback: Mary Barnes, Dave Cridland, Dave Crocker, Adrian Georgescu,
500 Christer Holmberg, Saul Ibarra Corretge, Olle Johansson, Paul
501 Kyzivat, Salvatore Loreto, Daniel-Constantin Mierla, and Tory Patnoe.
503 The authors gratefully acknowledge the assistance of Markus Isomaki
504 and Yana Stamcheva as the working group chairs and Gonzalo Camarillo
505 and Alissa Cooper as the sponsoring Area Directors.
507 Peter Saint-Andre wishes to acknowledge Cisco Systems, Inc., for
508 employing him during his work on earlier versions of this document.
510 Authors' Addresses
512 Peter Saint-Andre
513 &yet
514 P.O. Box 787
515 Parker, CO 80134
516 USA
518 Email: ietf@stpeter.im
519 Avshalom Houri
520 IBM
521 Rorberg Building, Pekris 3
522 Rehovot 76123
523 Israel
525 Email: avshalom@il.ibm.com
527 Joe Hildebrand
528 Cisco Systems, Inc.
529 1899 Wynkoop Street, Suite 600
530 Denver, CO 80202
531 USA
533 Email: jhildebr@cisco.com