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2 Network Working Group P. Saint-Andre
3 Internet-Draft &yet
4 Intended status: Standards Track A. Houri
5 Expires: December 12, 2014 IBM
6 J. Hildebrand
7 Cisco Systems, Inc.
8 June 10, 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-09
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 December 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),
92 since that is how existing systems solve the interworking problem.
94 Both XMPP and IM-capable SIP systems enable entities to exchange
95 "instant messages". The term "instant message" usually refers to a
96 message sent between two entities for delivery in close to real time
97 (rather than a message that is stored and forwarded to the intended
98 recipient upon request). This document covers single messages only
99 (sometimes called "pager-mode" messaging), since they form the lowest
100 common denominator for IM. Separate documents cover one-to-one chat
101 sessions [I-D.ietf-stox-chat] and multi-party groupchat
102 [I-D.ietf-stox-groupchat].
104 The architectural assumptions underlying such direct mappings are
105 provided in [RFC7247], including mapping of addresses and error
106 conditions. The mappings specified in this document cover basic
107 instant messaging functionality, i.e., the exchange of a single
108 instant message between a SIP user and an XMPP user in either
109 direction. Mapping of more advanced functionality is out of scope
110 for this document, but other documents in this "series" cover such
111 topics.
113 2. Intended Audience
115 The documents in this series are intended for use by software
116 developers who have an existing system based on one of these
117 technologies (e.g., SIP), and would like to enable communication from
118 that existing system to systems based on the other technology (e.g.,
119 XMPP). We assume that readers are familiar with the core
120 specifications for both SIP [RFC3261] and XMPP [RFC6120], with the
121 base document for this series [RFC7247], and with the following IM-
122 related specifications:
124 o Session Initiation Protocol (SIP) Extension for Instant Messaging
125 [RFC3428]
127 o Extensible Messaging and Presence Protocol: Instant Messaging and
128 Presence [RFC6121]
130 3. Terminology
132 A number of terms used here are explained in [RFC3261], [RFC3428],
133 [RFC6120], and [RFC6121].
135 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
136 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
137 "OPTIONAL" in this document are to be interpreted as described in
138 [RFC2119].
140 4. XMPP to SIP
142 As described in [RFC6121], a single instant message is an XML
143 stanza of type "normal" sent over an XML stream (since
144 "normal" is the default for the 'type' attribute of the
145 stanza, the attribute is often omitted).
147 When the XMPP user Juliet wants to send an
148 instant message to Romeo, she interacts with her XMPP client, which
149 generates an XMPP stanza. The syntax of the
150 stanza, including required and optional elements and attributes, is
151 defined in [RFC6121] (for single instant messages, the value of the
152 'to' address SHOULD be a "bare JID" of the form
153 "localpart@domainpart"). The following is an example of such a
154 stanza:
156 Example 1: XMPP user sends message
158 |
160 | Art thou not Romeo, and a Montague?
161 |
163 Upon receiving such a message stanza, the XMPP server needs to
164 determine the identity of the domainpart in the 'to' address, which
165 it does by following the procedures explained in Section 5 of
166 [RFC7247]. If the domain is a SIP domain, the XMPP server will hand
167 off the message stanza to an XMPP-to-SIP gateway that natively
168 communicates with IM-aware SIP servers.
170 The XMPP-to-SIP gateway is then responsible for translating the XMPP
171 message stanza into a SIP MESSAGE request from the XMPP user to the
172 SIP user:
174 Example 2: XMPP user sends message (SIP transformation)
176 | MESSAGE sip:romeo@example.net SIP/2.0
177 | Via: SIP/2.0/TCP x2s.example.com;branch=z9hG4bK776sgdkse
178 | Max-Forwards: 70
179 | To: sip:romeo@example.net
180 | From: ;tag=12345
181 | Call-ID: D9AA95FD-2BD5-46E2-AF0F-6CFAA96BDDFA
182 | CSeq: 1 MESSAGE
183 | Content-Type: text/plain
184 | Content-Length: 35
185 |
186 | Art thou not Romeo, and a Montague?
188 The destination SIP server is responsible for delivering the message
189 to the intended recipient, and the recipient is responsible for
190 generating a response (e.g., 200 OK).
192 Example 3: SIP user agent indicates receipt of message
194 | SIP/2.0 200 OK
195 | Via: SIP/2.0/TCP x2s.example.com;branch=z9hG4bK776sgdkse
196 | From: sip:romeo@example.net;tag=vwxyz
197 | To: sip:juliet@example.com;tag=12345
198 | Call-ID: D9AA95FD-2BD5-46E2-AF0F-6CFAA96BDDFA
199 | CSeq: 1 MESSAGE
200 | Content-Length: 0
202 As described in [RFC3428], a downstream proxy could fork a MESSAGE
203 request, but it would return only one 200 OK to the gateway.
205 Note: This document does not specify handling of the 200 OK by the
206 XMPP-to-SIP gateway (e.g., to enable message acknowledgements).
207 See [I-D.ietf-stox-chat] for a mapping of message acknowledgements
208 in the context of one-to-one chat sessions.
210 The mapping of XMPP syntax to SIP syntax SHOULD be as shown in the
211 following table. (Mappings for several aspects not mentioned here
212 are specified in [I-D.ietf-stox-chat].)
214 Table 1: Message syntax mapping from XMPP to SIP
216 +-----------------------------+--------------------------+
217 | XMPP Element or Attribute | SIP Header or Contents |
218 +-----------------------------+--------------------------+
219 | | body of MESSAGE |
220 | | Subject |
221 | | Call-ID |
222 | from | From (1) |
223 | id | (no mapping) |
224 | to | To or Request-URI |
225 | type | (no mapping) (2) |
226 | xml:lang | Content-Language |
227 +-----------------------------+--------------------------+
229 1. As shown in the foregoing example and described in [RFC7247], the
230 XMPP-to-SIP gateway SHOULD map the bare JID
231 ("localpart@domainpart") of the XMPP sender to the SIP From
232 header and include the resourcepart of the full JID as the GRUU
233 portion [RFC5627] of the SIP URI.
235 2. Because there is no SIP header field that matches the meaning of
236 the XMPP message 'type' values ("normal", "chat", "groupchat",
237 "headline", "error"), no general mapping is possible here.
239 5. SIP to XMPP
241 As described in [RFC3428], a single instant message is a SIP MESSAGE
242 request sent from a SIP user agent to an intended recipient who is
243 most generally referenced by an Instant Message URI of the form
244 but who might be referenced by a SIP or SIPS URI of
245 the form or .
247 When the SIP user Romeo wants to send an
248 instant message to Juliet, he interacts with his SIP user agent,
249 which generates a SIP MESSAGE request. The syntax of the MESSAGE
250 request is defined in [RFC3428]. The following is an example of such
251 a request:
253 Example 4: SIP user sends message
255 | MESSAGE sip:juliet@example.com SIP/2.0
256 | Via: SIP/2.0/TCP s2x.example.net;branch=z9hG4bKeskdgs677
257 | Max-Forwards: 70
258 | To: sip:juliet@example.com
259 | From: sip:romeo@example.net;tag=vwxyz
260 | Call-ID: 9E97FB43-85F4-4A00-8751-1124FD4C7B2E
261 | CSeq: 1 MESSAGE
262 | Content-Type: text/plain
263 | Content-Length: 44
264 |
265 | Neither, fair saint, if either thee dislike.
267 Section 5 of [RFC3428] stipulates that a SIP User Agent presented
268 with an im: URI should resolve it to a sip: or sips: URI. Therefore
269 we assume that the Request-URI of a request received by an IM-capable
270 SIP-to-XMPP gateway will contain a sip: or sips: URI. Upon receiving
271 the MESSAGE, the SIP server needs to determine the identity of the
272 domain portion of the Request-URI or To header, which it does by
273 following the procedures explained in Section 5 of [RFC7247]. If the
274 domain is an XMPP domain, the SIP server will hand off the MESSAGE to
275 an associated SIP-to-XMPP gateway that natively communicates with
276 XMPP servers.
278 The SIP-to-XMPP gateway is then responsible for translating the
279 request into an XMPP message stanza from the SIP user to the XMPP
280 user and returning a SIP "200 OK" message to the sender:
282 Example 5: SIP user sends message (XMPP transformation)
284 |
286 | Neither, fair saint, if either thee dislike.
287 |
289 Note that the stanza handling rules specified in [RFC6121] allow the
290 receiving XMPP server to deliver a message stanza whose 'to' address
291 is a bare JID ("localpart@domainpart") to multiple connected devices.
292 This is similar to the "forking" of messages in SIP.
294 The mapping of SIP syntax to XMPP syntax SHOULD be as shown in the
295 following table. (Mappings for several aspects not mentioned here
296 are specified in [I-D.ietf-stox-chat].)
298 Table 2: Message syntax mapping from SIP to XMPP
300 +--------------------------+-----------------------------+
301 | SIP Header or Contents | XMPP Element or Attribute |
302 +--------------------------+-----------------------------+
303 | Call-ID | |
304 | Content-Language | xml:lang |
305 | CSeq | (no mapping) |
306 | From | from (1) |
307 | Subject | |
308 | Request-URI or To | to |
309 | body of MESSAGE | |
310 +--------------------------+-----------------------------+
312 1. As shown in the foregoing example and described in [RFC7247], if
313 the IM-capable SIP-to-XMPP gateway has information about the GRUU
314 [RFC5627] of the particular endpoint that sent the SIP message
315 then it SHOULD map the sender's address to a full JID
316 ("localpart@domainpart/resourcepart") in the 'from' attribute of
317 the XMPP stanza and include the GRUU as the resourcepart.
319 When transforming SIP pager-mode messages, an IM-capable SIP-to-XMPP
320 gateway SHOULD specify no XMPP 'type' attribute or, equivalently, a
321 'type' attribute whose value is "normal" [RFC6121].
323 See Section 6 of this document about the handling of SIP message
324 bodies that contain content types other than plain text.
326 6. Content Types
328 SIP requests of type MESSAGE are allowed to contain essentially any
329 content type. The recommended procedures for SIP-to-XMPP gateways to
330 use in handling these content types are as follows.
332 An IM-aware SIP-to-XMPP gateway MUST process SIP messages that
333 contain message bodies of type "text/plain" and MUST encapsulate such
334 message bodies as the XML character data of the XMPP element.
336 An IM-aware SIP-to-XMPP gateway SHOULD process SIP messages that
337 contain message bodies of type "text/html"; if so, a gateway MUST
338 transform the "text/html" content into XHTML content that conforms to
339 the XHTML-IM Integration Set specified in [XEP-0071].
341 Although an IM-aware SIP-to-XMPP gateway MAY process SIP messages
342 that contain message bodies of types other than "text/plain" and
343 "text/html", the handling of such content types is a matter of
344 implementation.
346 7. Internationalization Considerations
348 Both XMPP and SIP support the UTF-8 encoding [RFC3629] of Unicode
349 characters [UNICODE] within messages, and signalling of the language
350 for a particular message (in XMPP via the 'xml:lang' attribute and in
351 SIP via the Content-Language header). Several examples follow, using
352 the "XML Notation" [RFC3987] for Unicode characters outside the ASCII
353 range.
355 Example 6: SIP user sends message
357 | MESSAGE sip:juliet@example.com SIP/2.0
358 | Via: SIP/2.0/TCP s2x.example.net;branch=z9hG4bKeskdgs677
359 | Max-Forwards: 70
360 | To: sip:juliet@example.com
361 | From: sip:romeo@example.net;tag=vwxyz
362 | Call-ID: 9E97FB43-85F4-4A00-8751-1124FD4C7B2E
363 | CSeq: 1 MESSAGE
364 | Content-Type: text/plain
365 | Content-Length: 45
366 | Content-Language: cs
367 |
368 | Nic z ob쎩ho, m쎡 d쒛vo spanil쎡,
369 | nenavid쎭얡-li jedno nebo druh쎩.
371 Example 7: SIP user sends message (XMPP transformation)
373 |
376 |
377 | Nic z ob쎩ho, m쎡 d쒛vo spanil쎡,
378 | nenavid쎭얡-li jedno nebo druh쎩.
379 |
380 |
382 8. IANA Considerations
384 This document requests no actions of IANA.
386 9. Security Considerations
388 Detailed security considerations for instant messaging protocols are
389 given in [RFC2779], for SIP-based instant messaging in [RFC3428] (see
390 also [RFC3261]), and for XMPP-based instant messaging in [RFC6121]
391 (see also [RFC6120]). The security considerations provided in
392 [RFC7247] also apply.
394 This document specifies methods for exchanging instant messages
395 through a gateway that translates between SIP and XMPP. Such a
396 gateway MUST be compliant with the minimum security requirements of
397 the instant messaging protocols for which it translates (i.e., SIP
398 and XMPP). The addition of gateways to the security model of instant
399 messaging specified in [RFC2779] introduces some new risks. In
400 particular, end-to-end security properties (especially
401 confidentiality and integrity) between instant messaging user agents
402 that interface through an IM-capable SIP-to-XMPP gateway can be
403 provided only if common formats are supported. Specification of
404 those common formats is out of scope for this document, although it
405 is preferred to use [RFC3862] for instant messages.
407 10. References
409 10.1. Normative References
411 [I-D.ietf-stox-chat]
412 Saint-Andre, P. and S. Loreto, "Interworking between the
413 Session Initiation Protocol (SIP) and the Extensible
414 Messaging and Presence Protocol (XMPP): One-to-One Text
415 Chat Sessions", draft-ietf-stox-chat-07 (work in
416 progress), June 2014.
418 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
419 Requirement Levels", BCP 14, RFC 2119, March 1997.
421 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
422 A., Peterson, J., Sparks, R., Handley, M., and E.
423 Schooler, "SIP: Session Initiation Protocol", RFC 3261,
424 June 2002.
426 [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
427 and D. Gurle, "Session Initiation Protocol (SIP) Extension
428 for Instant Messaging", RFC 3428, December 2002.
430 [RFC5627] Rosenberg, J., "Obtaining and Using Globally Routable User
431 Agent URIs (GRUUs) in the Session Initiation Protocol
432 (SIP)", RFC 5627, October 2009.
434 [RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
435 Protocol (XMPP): Core", RFC 6120, March 2011.
437 [RFC6121] Saint-Andre, P., "Extensible Messaging and Presence
438 Protocol (XMPP): Instant Messaging and Presence", RFC
439 6121, March 2011.
441 [RFC7247] Saint-Andre, P., Houri, A., and J. Hildebrand,
442 "Interworking between the Session Initiation Protocol
443 (SIP) and the Extensible Messaging and Presence Protocol
444 (XMPP): Architecture, Addresses, and Error Handling", RFC
445 7247, May 2014.
447 [XEP-0071]
448 Saint-Andre, P., "XHTML-IM", XSF XEP 0071, November 2012.
450 10.2. Informative References
452 [I-D.ietf-simple-cpim-mapping]
453 Rosenberg, J. and B. Campbell, "CPIM Mapping of SIMPLE
454 Presence and Instant Messaging", draft-ietf-simple-cpim-
455 mapping-01 (work in progress), June 2002.
457 [I-D.ietf-stox-groupchat]
458 Saint-Andre, P., Corretge, S., and S. Loreto,
459 "Interworking between the Session Initiation Protocol
460 (SIP) and the Extensible Messaging and Presence Protocol
461 (XMPP): Groupchat", draft-ietf-stox-groupchat-04 (work in
462 progress), March 2014.
464 [RFC2779] Day, M., Aggarwal, S., and J. Vincent, "Instant Messaging
465 / Presence Protocol Requirements", RFC 2779, February
466 2000.
468 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
469 10646", STD 63, RFC 3629, November 2003.
471 [RFC3860] Peterson, J., "Common Profile for Instant Messaging
472 (CPIM)", RFC 3860, August 2004.
474 [RFC3862] Klyne, G. and D. Atkins, "Common Presence and Instant
475 Messaging (CPIM): Message Format", RFC 3862, August 2004.
477 [RFC3922] Saint-Andre, P., "Mapping the Extensible Messaging and
478 Presence Protocol (XMPP) to Common Presence and Instant
479 Messaging (CPIM)", RFC 3922, October 2004.
481 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
482 Identifiers (IRIs)", RFC 3987, January 2005.
484 [UNICODE] The Unicode Consortium, "The Unicode Standard, Version
485 6.3", 2013,
486 .
488 Appendix A. Acknowledgements
490 The authors wish to thank the following individuals for their
491 feedback: Mary Barnes, Dave Cridland, Dave Crocker, Adrian Georgescu,
492 Christer Holmberg, Saul Ibarra Corretge, Olle Johansson, Paul
493 Kyzivat, Salvatore Loreto, Daniel-Constantin Mierla, and Tory Patnoe.
495 The authors gratefully acknowledge the assistance of Markus Isomaki
496 and Yana Stamcheva as the working group chairs and Gonzalo Camarillo
497 and Alissa Cooper as the sponsoring Area Directors.
499 Peter Saint-Andre wishes to acknowledge Cisco Systems, Inc., for
500 employing him during his work on earlier versions of this document.
502 Authors' Addresses
504 Peter Saint-Andre
505 &yet
506 P.O. Box 787
507 Parker, CO 80134
508 USA
510 Email: peter@andyet.com
511 Avshalom Houri
512 IBM
513 Rorberg Building, Pekris 3
514 Rehovot 76123
515 Israel
517 Email: avshalom@il.ibm.com
519 Joe Hildebrand
520 Cisco Systems, Inc.
521 1899 Wynkoop Street, Suite 600
522 Denver, CO 80202
523 USA
525 Email: jhildebr@cisco.com