Network Working Group P. Saint-Andre Internet-Draft Jabber Software Foundation Expires: August 8, 2004 A. Houri IBM J. Hildebrand Jabber, Inc. February 8, 2004 Interoperability between the Extensible Messaging and Presence Protocol (XMPP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) draft-saintandre-xmpp-simple-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 8, 2004. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document defines a bi-directional protocol mapping for use by gateways that enable the exchange of instant messages and presence information between systems that implement the Extensible Messaging and Presence Protocol (XMPP) and those that implement SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE). Saint-Andre, et al. Expires August 8, 2004 [Page 1] Internet-Draft XMPP SIMPLE Interop February 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 XMPP to SIMPLE . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 SIMPLE to XMPP . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Instant Messages . . . . . . . . . . . . . . . . . . . . . . . 6 3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2 XMPP to SIMPLE . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3 SIMPLE to XMPP . . . . . . . . . . . . . . . . . . . . . . . . 9 4. Presence Information . . . . . . . . . . . . . . . . . . . . . 10 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.2 XMPP to SIMPLE . . . . . . . . . . . . . . . . . . . . . . . . 10 4.3 SIMPLE to XMPP . . . . . . . . . . . . . . . . . . . . . . . . 12 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 Normative References . . . . . . . . . . . . . . . . . . . . . 14 Informative References . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . . 17 Saint-Andre, et al. Expires August 8, 2004 [Page 2] Internet-Draft XMPP SIMPLE Interop February 2004 1. Introduction In order to help ensure interoperability between instant messaging and presence systems that conform to the requirements of RFC 2779 [IMP-REQS], it is important to clearly define mappings between such protocols. Within the IETF, work has proceeded on two such protocols: SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE), which consists of extensions to the Session Initiation Protocol ([SIP]), and the Extensible Messaging and Presence Protocol (XMPP), which consists of a formalization of the core XML streaming protocols developed originally by the Jabber open-source community. One approach to helping ensure interoperability between such protocols is to map each protocol to the abstract semantics described in [CPIM] and [CPP]; that is the approach taken by [SIMPLE-CPIM] and [XMPP-CPIM]. Another approach is that taken by [DRAFT-UMPP]. The approach taken in this document is to directly map semantics from one protocol to another (i.e., from SIMPLE to XMPP and vice-versa), mainly for use by gateways between systems that implement one or the other of these protocols. (These approaches describe concepts that are complementary in many ways, and a future draft may provide a more substantive merger between them.) The mappings specified in this document cover three main areas: o Mapping of addresses o Mapping of instant messages o Mapping of presence information It is important to note that an underlying architectural assumption for this document is that the mapping between protocols will most likely occur by means of a gateway between an XMPP network and a SIMPLE network. Such a gateway is a dedicated translator between the XMPP and SIMPLE protocols, which naturally may be co-resident with an XMPP server or a SIMPLE server. Although such a gateway could use the [CPIM] and [CPP] specifications to define the common formats into which the protocols are translated for purposes of interworking (as specified in [SIMPLE-CPIM] and [XMPP-CPIM].), this document assumes that a SIMPLE-XMPP gateway will translate directly from one protocol to the other. 1.1 Terminology The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [TERMS]. Saint-Andre, et al. Expires August 8, 2004 [Page 3] Internet-Draft XMPP SIMPLE Interop February 2004 2. Addresses 2.1 Overview The address formats used to identify XMPP entities are different from those used to identify SIP/SIMPLE entities. The XMPP address format is specified in [XMPP-CORE]; as specified in [XMPP-IM], instant messaging and presence applications of XMPP MUST also support 'im:' and 'pres:' URIs as specified in [CPIM] and [CPP] respectively. The SIP/SIMPLE address format for instant messaging is specified in [SIP-IM]; it may use either 'sip:' or 'sips:' URIs as specified in [SIP] or an 'im:' URI as specified in [CPIM]. The SIP/SIMPLE address format for presence is specified in [SIP-PRES]; it may use either 'sip:' or 'sips:' URIs as specified in [SIP] or a 'pres:' URI as specified in [CPP]. In this document we describe mappings for addresses of the form only, ignoring any protocol-specific extensions such as XMPP resource identifiers or SIP telephone numbers and passwords. However, we have ruled the mapping of domain names as out of scope for the initial version of this document, since it is a matter for the Domain Name System and the translation of fully internationalized domain names (which the SIP address format does not allow, but which the XMPP address format does allow via [IDNA]) into non-internationalized domain names. Therefore in the following sections we treat local-part addresses only (these are called variously "usernames", "instant inboxes", "presentities", and "node identifiers" in the protocols at issue). The sip:/sips:, im:/pres:, and XMPP address schemes allow different sets of characters. In some cases, characters allowed in one scheme are disallowed in others; these characters must be mapped appropriately in order to ensure interoperable communications across systems. The table below summarizes our findings regarding the complement of allowable US-ASCII characters in each addressing scheme when compared individually to the other schemes. Table 1: Partial complements of allowable US-ASCII characters +----------+----------+-----------+-------+ | | SIP/SIPS | IM/PRES | XMPP | +----------+----------+-----------+-------+ | SIP/SIPS | N/A | (),; | &'/ | +----------+----------+-----------+-------+ | IM/PRES | #%^`{|} | N/A | &'/ | +----------+----------+-----------+-------+ | XMPP | none | none | N/A | +----------+----------+-----------+-------+ Saint-Andre, et al. Expires August 8, 2004 [Page 4] Internet-Draft XMPP SIMPLE Interop February 2004 Note: Each cell shows US-ASCII characters that are disallowed in the column protocol but allowed in the row protocol; e.g., the last cell of the third row shows that the characters &'/ are allowed in sip:/ sips: URIs but disallowed in XMPP addresses. The table below is another way of looking at the same issue, since it shows the intersection of allowable US-ASCII characters in each addressing scheme when compared individually to the other schemes. Table 2: Partial intersections of allowable US-ASCII characters +-------------------+------------------+----------------------+ | SIP/SIPS & XMPP | IM/PRES & XMPP | SIP/SIPS & IM/PRES | +-------------------+------------------+----------------------+ | a-z A-Z 0-9 | a-z A-Z 0-9 | a-z A-Z 0-9 | | !$()*+,-.;=?_~ | !#$%*+-.=?^_` | !$*+-.=?_~ | | %hexhex | {|}~ | | +-------------------+------------------+----------------------+ Therefore the following US-ASCII characters are allowed in all three addressing schemes (i.e., the intersection of all three sets of allowable characters): a-z A-Z 0-9 ! $ * + - . = ? In addition to the US-ASCII characters described above, many non-US-ASCII (specifically, UTF-8) characters are allowed in XMPP addresses but not allowed in sip:/sips: or im:/pres: URIs, since XMPP allows internationalized local-part addresses. A straightforward mapping of these characters to US-ASCII characters is provided in Section 2.2.5 of [URL-GUIDE], namely to encode unsafe octets using the %hexhex encoding. 2.2 XMPP to SIMPLE The following is a high-level algorithm for mapping an XMPP address to a sip:, sips:, im:, or pres: URI: 1. Split XMPP address into node identifier (local-part; mapping described in remaining steps), domain identifier (hostname; mapping is out of scope), and resource identifier (specifier for particular device or connection; discard this for cross-system interoperability) 2. Apply Nodeprep profile of [STRINGPREP] (as specified in [XMPP-CORE]) for canonicalization (OPTIONAL) 3. Translate #26; to &, #27; to ', and #2f; to / respectively Saint-Andre, et al. Expires August 8, 2004 [Page 5] Internet-Draft XMPP SIMPLE Interop February 2004 4. For each byte, if the byte is not in the set -A-Za-z0-9!$*.?_~+= then change to %hexhex 5. Combine resulting local-part with mapped hostname to form local@domain address 6. Prepend with 'im:' scheme (for XMPP stanzas) or 'pres:' scheme (for XMPP stanzas) if foreign domain supports these (discovered via [SRV] lookup as specified in [XMPP-IM]), else prepend with 'sip:' or 'sips:' scheme according to local service policy 2.3 SIMPLE to XMPP The following is a high-level algorithm for mapping a sip:, sips:, im:, or pres: URI to an XMPP address: 1. Remove URI scheme 2. Split at the first '@' character into local-part and hostname (mapping the latter is out of scope) 3. Translate %hexhex to equivalent octets 4. Treat result as a UTF-8 string 5. Translate & to #26;, ' to #27;, and / to @2f respectively 6. Apply Nodeprep profile of [STRINGPREP] (as specified in [XMPP-CORE]) for canonicalization (OPTIONAL) 7. Recombine local-part with mapped hostname to form local@domain address 3. Instant Messages 3.1 Overview Both XMPP and SIMPLE systems enable entities (often but not necessarily human users) to send "instant messages" to other entities. The term "instant message" usually refers to messages sent between two entities for delivery in close to real time (rather than messages that are stored and forwarded to the intended recipient upon request). Generally there are three kinds of instant message: Saint-Andre, et al. Expires August 8, 2004 [Page 6] Internet-Draft XMPP SIMPLE Interop February 2004 o Single messages, which are sent from the sender to the recipient outside the context of any one-to-one chat session or multi-user text conference. o Chat messages, which are sent from the sender to the recipient in the context of a "message session" between the two entities. o Groupchat messages, which are sent from a sender to multiple recipients in the context of a text conference (along the lines of [IRC]). This document addresses single messages only, since they form the "lowest common denominator" for instant messaging on the Internet. It is likely that future versions of this document will address chat messages as well, especially once the SIMPLE WG completes its work on one-to-one message sessions (a likely candidate for finalization is [SIMPLE-MSRP]). Instant messaging using XMPP message stanzas of type "normal" is specified in [XMPP-IM]. SIP/SIMPLE instant messaging using SIP requests of type MESSAGE (often called "pager-model" messaging) is specified in [SIP-IM]. As described in [XMPP-IM], a single instant message is an XML stanza of type "normal" sent over an XML stream (since "normal" is the default for the 'type' attribute of the stanza, the attribute is often omitted). In this document we will assume that such a message is sent from an XMPP client to an XMPP server over an XML stream negotiated between the client and the server, and that the client is controlled by a human user (this is a simplifying assumption introduced for explanatory purposes only; the XMPP sender could be a bot-controlled client, a component such as a workflow application, a server, etc.). Continuing the tradition of Shakespeare examples in XMPP documentation, we will say that the XMPP user has an XMPP address of . As described in [SIP-IM], a single instant message is a SIP MESSAGE request sent from a SIP user agent to an intended recipient who is most generally referenced by an Instant Message URI of the form "im:user@domain" but who may be referenced by a SIP or SIPS URI of the form "sip:user@domain" or "sips:user@domain". Here again we introduce the simplifying assumption that the user agent is controlled by a human user, whom we shall dub . 3.2 XMPP to SIMPLE When Juliet wants to send an instant message to Romeo, she interacts with her XMPP client, which generates an XMPP stanza. The Saint-Andre, et al. Expires August 8, 2004 [Page 7] Internet-Draft XMPP SIMPLE Interop February 2004 syntax of the stanza, including required and optional elements and attributes, is defined in [XMPP-IM]. The following is an example of such a stanza: Example: An XMPP message stanza: Art thou not Romeo, and a Montague? Upon receiving such a stanza, the XMPP server to which Juliet has connected either delivers it to a local recipient (if the hostname in the 'to' attribute matches one of the hostnames serviced by the XMPP server) or attempts to route it to the foreign domain that services the hostname in the 'to' attribute. Naturally, in this document we assume that the hostname in the 'to' attribute is a SIMPLE instant messaging service hosted by a separate server. As specified in [XMPP-IM], the XMPP server needs to determine the identity of the foreign domain, which it does by performing one or more [SRV] lookups. For message stanzas, the order of lookups recommended by [XMPP-IM] is to first try the "_xmpp-server" service as specified in [XMPP-CORE] and to then try the "_im" service as specified in [IMP-SRV]. Here we assume that the first lookup will fail but that the second lookup will succeed and return a resolution "_im._simple.example.net.", since we have already assumed that the example.net hostname is running a SIMPLE instant messaging service. (Note: The XMPP server may have previously determined that the foreign domain is a SIMPLE server, in which case it would not need to perform the SRV lookups; the caching of such information is a matter of implementation and local service policy, and is therefore out of scope for this document.) Once the XMPP server has determined that the foreign domain is serviced by a SIMPLE server, it must determine how to proceed. We here assume that the XMPP server contains or has available to it an XMPP-SIMPLE gateway. The XMPP server would then deliver the message stanza to the XMPP-SIMPLE gateway. The XMPP-SIMPLE gateway is then responsible for translating the XMPP message stanza into a SIP MESSAGE request from the XMPP user to the SIMPLE user: Example: A SIP MESSAGE request: MESSAGE sip:romeo@example.net SIP/2.0 Via: SIP/2.0/TCP julietpc.example.com;branch=z9hG4bK776sgdkse Max-Forwards: 70 Saint-Andre, et al. Expires August 8, 2004 [Page 8] Internet-Draft XMPP SIMPLE Interop February 2004 From: sip:juliet@example.com;tag=49583 To: sip:romeo@example.net Call-ID: Hr0zny9l3@example.com CSeq: 1 MESSAGE Content-Type: text/plain Content-Length: 37 Art thou not Romeo, and a Montague? Detailed recommendations regarding mapping or generation of SIP MESSAGE header fields by an XMPP-SIMPLE gateway will be provided in a future revision of this document. 3.3 SIMPLE to XMPP When Romeo wants to send an instant message to Juliet, he interacts with his SIP user agent, which generates a SIP MESSAGE request. The syntax of the MESSAGE request is defined in [SIP-IM]. The following is an example of such a request: Example: Another SIP MESSAGE request: MESSAGE sip:juliet@example.com SIP/2.0 Via: SIP/2.0/TCP romeopc.example.com;branch=eskdgs677Kb4Ghz9 Max-Forwards: 70 From: sip:romeo@example.net;tag=38594 To: sip:juliet@example.com Call-ID: M4spr4vdu@example.net CSeq: 1 MESSAGE Content-Type: text/plain Content-Length: 26 Neither, fair saint, if either thee dislike. Upon receiving such a request, a SIMPLE-XMPP gateway is responsible for translating it into an XMPP message stanza from the SIP user to the XMPP user: Example: Another XMPP message stanza: Neither, fair saint, if either thee dislike. Detailed recommendations regarding mapping or generation of XMPP message stanza elements and attributes by a SIMPLE-XMPP gateway will be provided in a future revision of this document. Saint-Andre, et al. Expires August 8, 2004 [Page 9] Internet-Draft XMPP SIMPLE Interop February 2004 4. Presence Information 4.1 Overview Both XMPP and SIMPLE systems enable entities (often but not necessarily human users) to send presence to other entities. At a minimum, the term "presence" refers to information about an entity's availability for communication on a network (on/off), often supplemented by information that further specifies the entity's communications context (e.g., "do not disturb"). Some systems and protocols extend this notion even further and refer to any relatively ephemeral information about an entity as a kind of presence; categories of such "extended presence" include geographical location (e.g., GPS coordinates), user mood (e.g., grumpy), user activity (e.g., walking), and ambient environment (e.g., noisy). In this document, we focus on the "least common denominator" of network availability only, although future revisions of this document may address broader notions of presence. In addition, we address presence notifications only, not presence subscriptions. Presence using XMPP presence stanzas of type "available" or "unavailable" is specified in [XMPP-IM]. SIP/SIMPLE presence using a SIP event package for presence is specified in [SIP-PRES]. As described in [XMPP-IM], presence information about an entity is communicated by means of an XML stanza sent over an XML stream. In this document we will assume that such a presence stanza is sent from an XMPP client to an XMPP server over an XML stream negotiated between the client and the server, and that the client is controlled by a human user (again, this is a simplifying assumption introduced for explanatory purposes only). In general, XMPP presence is sent by the user to the user's server and then broadcasted to all entities who are subscribed to the user's presence information. As described in [SIP-PRES], presence information about an entity is communicated by means of a SIP NOTIFY event sent from a SIP user agent to an intended recipient who is most generally referenced by an Instant Message URI of the form "pres:user@domain" but who may be referenced by a SIP or SIPS URI of the form "sip:user@domain" or "sips:user@domain". Here again we introduce the simplifying assumption that the user agent is controlled by a human user. 4.2 XMPP to SIMPLE When Juliet interacts with her XMPP client to modify her presence information (or when her client automatically updates her presence information, e.g. via an "auto-away" feature), her client generates an XMPP stanza. The syntax of the stanza, Saint-Andre, et al. Expires August 8, 2004 [Page 10] Internet-Draft XMPP SIMPLE Interop February 2004 including required and optional elements and attributes, is defined in [XMPP-IM]. The following is an example of such a stanza: Example: An XMPP presence stanza: Upon receiving such a stanza, the XMPP server to which Juliet has connected broadcasts it to all subscribers who are authorized to receive presence notifications from Juliet. For each subscriber, broadcasting the presence notification involves either delivering it to a local recipient (if the hostname in the subscriber's address matches one of the hostnames serviced by the XMPP server) or attempting to route it to the foreign domain that services the hostname in the subscriber's address. Naturally, in this document we assume that the hostname is a SIMPLE presence service hosted by a separate server. As specified in [XMPP-IM], the XMPP server needs to determine the identity of the foreign domain, which it does by performing one or more [SRV] lookups. For presence stanzas, the order of lookups recommended by [XMPP-IM] is to first try the "_xmpp-server" service as specified in [XMPP-CORE] and to then try the "_pres" service as specified in [IMP-SRV]. Here we assume that the first lookup will fail but that the second lookup will succeed and return a resolution "_pres._simple.example.net.", since we have already assumed that the example.net hostname is running a SIMPLE presence service. (Note: The XMPP server may have previously determined that the foreign domain is a SIMPLE server, in which case it would not need to perform the SRV lookups; the caching of such information is a matter of implementation and local service policy, and is therefore out of scope for this document.) Once the XMPP server has determined that the foreign domain is serviced by a SIMPLE server, it must determine how to proceed. We here assume that the XMPP server contains or has available to it an XMPP-SIMPLE gateway. The XMPP server would then deliver the presence stanza to the XMPP-SIMPLE gateway. The XMPP-SIMPLE gateway is then responsible for translating the XMPP presence stanza into a SIP NOTIFY request and included PIDF document from the XMPP user to the SIMPLE user: Example: A SIP NOTIFY request: NOTIFY sip:romeo@example.net SIP/2.0 Via: SIP/2.0/TCP simple.example.net;branch=z9hG4bKna998sk From: ;tag=ffd2 To: ;tag=xfg9 Call-ID: j4s0h4vny@example.com Saint-Andre, et al. Expires August 8, 2004 [Page 11] Internet-Draft XMPP SIMPLE Interop February 2004 Event: presence Subscription-State: active;expires=599 Max-Forwards: 70 CSeq: 8775 NOTIFY Contact: sip:simple.example.net Content-Type: application/cpim-pidf+xml Content-Length: 192 open Detailed recommendations regarding mapping or generation of SIP NOTIFY header fields and PIDF document elements and attributes by an XMPP-SIMPLE gateway will be provided in a future revision of this document. 4.3 SIMPLE to XMPP When Romeo changes his presence, his SIP user agent generates a SIP NOTIFY request. The syntax of the NOTIFY request is defined in [SIP-PRES]. The following is an example of such a request: Example: Another SIP NOTIFY request: NOTIFY sip:juliet@example.com SIP/2.0 Via: SIP/2.0/TCP simple.example.net;branch=z9hG4bKna998sk From: ;tag=ffd2 To: ;tag=xfg9 Call-ID: j0sj4sv1m@example.net Event: presence Subscription-State: active;expires=599 Max-Forwards: 70 CSeq: 8775 NOTIFY Contact: sip:simple.example.net Content-Type: application/cpim-pidf+xml Content-Length: 193 Saint-Andre, et al. Expires August 8, 2004 [Page 12] Internet-Draft XMPP SIMPLE Interop February 2004 closed Upon receiving such a request, a SIMPLE-XMPP gateway is responsible for translating it into an XMPP presence stanza from the SIP user to the XMPP user: Example: Another XMPP presence stanza: Detailed recommendations regarding mapping or generation of XMPP presnce stanza elements and attributes by a SIMPLE-XMPP gateway will be provided in a future revision of this document. 5. IANA Considerations This document requires no action on the part of the IANA. 6. Security Considerations Detailed security considerations for instant messaging and presence protocols are given in [IMP-REQS], specifically in Sections 5.1 through 5.4. Detailed security considerations for XMPP are given in XMPP Core [XMPP-CORE]. Detailed security considerations for SIMPLE messaging are given in [SIP-IM] and for SIMPLE presence are given in [SIP-PRES] (see also the security considerations for the Session Initiation Protocol given in [SIP]). This document specifies methods for exchanging instant messages and presence information through a gateway that translates between SIMPLE and XMPP. Such a gateway MUST be compliant with the minimum security requirements of the instant messaging and presence protocols for which it translates (i.e., SIMPLE and XMPP). The introduction of gateways to the security model of instant messaging and presence specified in [IMP-REQS] introduces some new risks. In particular, end-to-end security properties (especially confidentiality and integrity) between instant messaging and presence 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 [MSGFMT] for instant messages and [PIDF] for presence. Saint-Andre, et al. Expires August 8, 2004 [Page 13] Internet-Draft XMPP SIMPLE Interop February 2004 7. Open Issues This document has made certain simplifying assumptions and has ruled a number of problematic issues out of scope for now. However, future revisions of this document will attempt to address these issues, which include: o Internationalized domain names o Chat messages / instant messaging sessions o Presence subscriptions o More detailed syntax mappings o Error handling and specific conditions o Address resolution (including SRV lookups) from SIMPLE to XMPP o End-to-end object encryption using common formats (e.g., PIDF for presence) o Ensuring end-to-end channel encryption using TLS o Blocking communications (whitelisting/blacklisting) across systems 8. Acknowledgements The authors wish to thank Nathaniel Borenstein and Rohan Mahy for suggestions and encouragement. Normative References [IMP-SRV] Peterson, J., "Address Resolution for Instant Messaging and Presence", draft-ietf-impp-srv-04 (work in progress), October 2003. [PIDF] Fujimoto, S., Sugano, H., Klyne, G., Bateman, A., Carr, W. and J. Peterson, "CPIM Presence Information Data Format", draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. [SIP] 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. [SIP-IM] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C. and D. Gurle, "Session Initiation Protocol (SIP) Extension Saint-Andre, et al. Expires August 8, 2004 [Page 14] Internet-Draft XMPP SIMPLE Interop February 2004 for Instant Messaging", RFC 3428, December 2002. [SIP-PRES] Rosenberg, J., "A Presence Event Package for the Session Initiation Protocol (SIP)", draft-ietf-simple-presence-10 (work in progress), January 2003. [SRV] Gulbrandsen, A., Vixie, P. and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782, February 2000. [STRINGPREP] Hoffman, P. and M. Blanchet, "Preparation of Internationalized Strings ("STRINGPREP")", RFC 3454, December 2002. [TERMS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [URL-GUIDE] Masinter, L., Alvestrand, H., Zigmond, D. and R. Petke, "Guidelines for new URL Schemes", RFC 2718, November 1999. [XMPP-CORE] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Core", draft-ietf-xmpp-core-22 (work in progress), January 2004. [XMPP-IM] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence", draft-ietf-xmpp-im-21 (work in progress), January 2004. Informative References [CPIM] Peterson, J., "Common Profile for Instant Messaging (CPIM)", draft-ietf-impp-im-04 (work in progress), August 2003. [CPP] Peterson, J., "Common Profile for Presence (CPP)", draft-ietf-impp-pres-04 (work in progress), August 2003. [DRAFT-UMPP] Mahy, R., "A Unified Proposal for Server-to-Server Presence and Instant Messaging", draft-mahy-impp-unified-proposal-00 (work in progress), February 2004. [IDNA] Faltstrom, P., Hoffman, P. and A. Costello, Saint-Andre, et al. Expires August 8, 2004 [Page 15] Internet-Draft XMPP SIMPLE Interop February 2004 "Internationalizing Domain Names in Applications (IDNA)", RFC 3490, March 2003. [IMP-MODEL] Day, M., Rosenberg, J. and H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778, February 2000. [IMP-REQS] Day, M., Aggarwal, S. and J. Vincent, "Instant Messaging / Presence Protocol Requirements", RFC 2779, February 2000. [IRC] Oikarinen, J. and D. Reed, "Internet Relay Chat Protocol", RFC 1459, May 1993. [MSGFMT] Atkins, D. and G. Klyne, "Common Presence and Instant Messaging: Message Format", draft-ietf-impp-cpim-msgfmt-08 (work in progress), January 2003. [SIMPLE-CPIM] Rosenberg, J. and B. Campbell, "CPIM Mapping of SIMPLE Presence and Instant Messaging", draft-ietf-simple-cpim-mapping-01 (work in progress), June 2002. [SIMPLE-MSRP] Campbell, B., Rosenberg, J., Sparks, R. and P. Kyzivat, "The Message Session Relay Protocol", draft-ietf-simple-message-sessions-03 (work in progress), January 2004. [XMPP-CPIM] Saint-Andre, P., "XMPP CPIM Mapping", draft-ietf-xmpp-cpim-03 (work in progress), November 2003. Authors' Addresses Peter Saint-Andre Jabber Software Foundation Avshalom Houri IBM Joe Hildebrand Jabber, Inc. Saint-Andre, et al. Expires August 8, 2004 [Page 16] Internet-Draft XMPP SIMPLE Interop February 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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