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Versions: 00 01 02 04 05 draft-ietf-stox-core

Network Working Group                                     P. Saint-Andre
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                                A. Houri
Expires: December 15, 2013                                           IBM
                                                           J. Hildebrand
                                                     Cisco Systems, Inc.
                                                           June 13, 2013


   Interworking between the Session Initiation Protocol (SIP) and the
 Extensible Messaging and Presence Protocol (XMPP): Addresses and Error
                               Conditions
                   draft-saintandre-sip-xmpp-core-05

Abstract

   As a foundation for the definition of bidirectional protocol mappings
   between the Session Initiation Protocol (SIP) and the Extensible
   Messaging and Presence Protocol (XMPP), this document specifies the
   architectural assumptions underlying such mappings as well as the
   mapping of addresses and error conditions.

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 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
   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.  Architectural Assumptions  . . . . . . . . . . . . . . . . . .  3
   4.  Address Mapping  . . . . . . . . . . . . . . . . . . . . . . .  5
     4.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  5
     4.2.  Local Part Mapping . . . . . . . . . . . . . . . . . . . .  6
     4.3.  Instance-Specific Mapping  . . . . . . . . . . . . . . . .  7
     4.4.  SIP to XMPP  . . . . . . . . . . . . . . . . . . . . . . .  8
     4.5.  XMPP to SIP  . . . . . . . . . . . . . . . . . . . . . . .  8
   5.  Error Condition Mapping  . . . . . . . . . . . . . . . . . . .  9
     5.1.  XMPP to SIP  . . . . . . . . . . . . . . . . . . . . . . . 10
     5.2.  SIP to XMPP  . . . . . . . . . . . . . . . . . . . . . . . 10
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Appendix A.  Acknowledgements  . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14























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1.  Introduction

   The IETF has worked on two signalling technologies that can be used
   for multimedia session negotiation, messaging, presence, capabilities
   discovery, notifications, and other application-level functionality:

   o  The Session Initiation Protocol [RFC3261], along with various SIP
      extensions developed within the SIP for Instant Messaging and
      Presence Leveraging Extensions (SIMPLE) Working Group.
   o  The Extensible Messaging and Presence Protocol [RFC6120], along
      with various XMPP extensions developed by the IETF as well as by
      the XMPP Standards Foundation.

   Because these technologies are widely deployed, it is important to
   clearly define mappings between them for the sake of interworking.
   This document inaugurates a series of SIP-XMPP interworking
   specifications by defining the architectural assumptions underlying
   such mappings as well as the mapping of addresses and error
   conditions.

   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].


3.  Architectural Assumptions

   Protocol translation between SIP and XMPP could occur in a number of
   different entities, depending on the architecture of real-time
   communication deployments.  For example, protocol translation could
   occur within a multi-protocol server (which uses application-specific
   connection managers to initiate traffic to and accept traffic from
   clients or other servers natively using SIP/SIMPLE, XMPP, etc.),
   within a multi-protocol client (which enables a user to establish
   connections natively with various servers using SIP/SIMPLE, XMPP,
   etc.), or within a gateway that acts as a dedicated protocol
   translator (which takes one protocol as input and provides another
   protocol as output).

   This document assumes that the protocol translation will occur within



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   a gateway.  (This assumption not meant to discourage protocol
   translation within multi-protocol clients or servers; instead, this
   assumption is followed mainly to clarify the discussion and examples
   so that the protocol translation principles can be more easily
   understood and can be applied by client and server implementors with
   appropriate modifications to the examples and terminology.)
   Specifically, we assume that the protocol translation will occur
   within an "XMPP-to-SIP gateway" that translates XMPP syntax and
   semantics on behalf of an XMPP service when communicating with SIP
   services and/or within a "SIP-to-XMPP gateway" that translates SIP
   syntax and semantics on behalf of a SIP service when communicating
   with XMPP services (naturally, these logical functions could occur in
   one and the same actual translator).

   This document assumes that a gateway will translate directly from one
   protocol to the other.  For the sake of the examples, we further
   assume that protocol translation will occur within a gateway in the
   source domain, so that information generated by the user of an XMPP
   service will be translated by a gateway within the trust domain of
   that XMPP service, and information generated by the user of a SIP
   service will be translated by a gateway within the trust domain of
   that SIP service.  However, nothing in this document ought to be
   taken as recommending against protocol translation at the destination
   domain.

   An architectural diagram for a possible gateway deployment is shown
   below, where the entities have the following significance and the "#"
   character is used to show the boundary of a trust domain:

   o  romeo@example.net -- a SIP user.
   o  example.net -- a SIP service with a gateway ("GW") to XMPP.
   o  juliet@example.com -- an XMPP user.
   o  example.com -- an XMPP service with a gateway ("GW") to SIP.

      ##@#######################################################
      #                           #                            #
      #    +-------------+----+   #   +----+-------------+     #
      #    | example.net | GW |---#---| GW | example.com |     #
      #    +-------------+----+   #   +----+-------------+     #
      #          |                #              |             #
      #     romeo@example.net     #        juliet@example.com  #
      #                           #                            #
      ##########################################################








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4.  Address Mapping

4.1.  Overview

   The basic SIP address format is a "sip:" or "sips:" URI as specified
   in [RFC3261].  When a SIP entity supports extensions for instant
   messaging it might be identified by an 'im:' URI as specified in the
   Common Profile for Instant Messaging [RFC3860] (see [RFC3428]) and
   when a SIP entity spports extensions for presence it might be
   identified by a 'pres:' URI as specified in the Common Profile for
   Presence [RFC3859] (see [RFC3856]).

   The XMPP address format is specified in [RFC6122]; as discussed in
   [RFC6121], instant messaging and presence applications of XMPP also
   need to support 'im:' and 'pres:' URIs as specified in [RFC3860] and
   [RFC3859] respectively, although such support might simply involve
   leaving resolution of such addresses up to an XMPP server.

   In this document we primarily describe mappings for addresses of the
   form <user@domain>; however, we also provide guidelines for mapping
   the addresses of specific user agent instances, which take the form
   of Globally Routable User Agent URIs (GRUUs) in SIP and
   "resourceparts" in XMPP.  Mapping of protocol-specific identifiers
   (such as telephone numbers) is out of scope for this specification.
   In addition, we have ruled the mapping of domain names as out of
   scope for now since that is a matter for the Domain Name System;
   specifically, the issue for interworking between SIP and XMPP relates
   to the translation of fully internationalized domain names (IDNs)
   into non-internationalized domain names (IDNs are not allowed in the
   SIP address format, but are allowed in the XMPP address via
   Internationalized Domain Names in Applications, see [RFC6122] and
   [I-D.ietf-xmpp-6122bis]).  Therefore, in the following sections we
   focus primarily on the local part of an address (these are called
   variously "usernames", "instant inboxes", "presentities", and
   "localparts" in the protocols at issue), secondarily on the instance-
   specific part of an address, and not at all on the domain-name part
   of an address.

   The sip:/sips:, im:/pres:, and XMPP address schemes allow different
   sets of characters (although all three allow alphanumeric characters
   and disallow both spaces and control characters).  In some cases,
   characters allowed in one scheme are disallowed in others; these
   characters need to be mapped appropriately in order to ensure
   interworking across systems.







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4.2.  Local Part Mapping

   The local part of a sip:/sips: URI inherits from the "userinfo" rule
   in [RFC3986] with several changes; here we discuss the SIP "user"
   rule only:

      user             =  1*( unreserved / escaped / user-unreserved )
      user-unreserved  =  "&" / "=" / "+" / "$" / "," / ";" / "?" / "/"
      unreserved       =  alphanum / mark
      mark             =  "-" / "_" / "." / "!" / "~" / "*" / "'"
                          / "(" / ")"

   Here we make the simplifying assumption that the local part of an
   im:/pres: URI inherits from the "dot-atom-text" rule in [RFC5322]
   rather than the more complicated "local-part" rule:

      dot-atom-text =  1*atext *("." 1*atext)
      atext         =  ALPHA / DIGIT /    ; Any character except
                       "!" / "#" / "$" /  ; controls, SP, and
                       "%" / "&" / "'" /  ; specials. Used for
                       "*" / "+" / "-" /  ; atoms.
                       "/" / "=" / "?" /
                       "^" / "_" / "`" /
                       "{" / "|" / "}" /
                       "~"

   The local part of an XMPP address allows any ASCII character except
   space, controls, and the " & ' / : < > @ characters.

   To summarize the foregoing information, the following table lists the
   allowed and disallowed characters in the local part of identifiers
   for each protocol (aside from the alphanumeric, space, and control
   characters), in order by hexadecimal character number (where each "A"
   row shows the allowed characters and each "D" row shows the
   disallowed characters).
















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   Table 1: Allowed and disallowed characters

   +---+----------------------------------+
   | SIP/SIPS CHARACTERS                  |
   +---+----------------------------------+
   | A | !  $ &'()*+,-./ ; = ?     _    ~ |
   | D |  "# %          : < > @[\]^ `{|}  |
   +---+----------------------------------+
   | IM/PRES CHARACTERS                   |
   +---+----------------------------------+
   | A | ! #$%&'  *+ - /   = ?    ^_`{|}~ |
   | D |  "     ()  , . :;< > @[\]        |
   +---+----------------------------------+
   | XMPP CHARACTERS                      |
   +---+----------------------------------+
   | A | ! #$%  ()*+,-.  ; = ? [\]^_`{|}~ |
   | D |  "   &'       /: < > @           |
   +---+----------------------------------+

   When transforming the local part of an address from one scheme to
   another, an application SHOULD proceed as follows:

   1.  Unescape any escaped characters in the source address (e.g., from
       SIP to XMPP unescape "%2F" to "/" and from XMPP to SIP unescape
       "\27" to "'").
   2.  Leave unmodified any characters that are allowed in the
       destination scheme.
   3.  Escape any characters that are allowed in the source scheme but
       reserved in the destination scheme, as escaping is defined for
       the destination scheme.  In particular:
       *  Where the destination scheme is a URI (i.e., an im:, pres:,
          sip:, or sips: URI), each reserved character MUST be percent-
          encoded to "%hexhex" as specified in Section 2.6 of [RFC4395]
          (e.g., when transforming from XMPP to SIP, encode "/" as
          "%2F").
       *  Where the destination scheme is a native XMPP address, each
          reserved character MUST be encoded to "\hexhex" as specified
          in [XEP-0106] (e.g., when transforming from SIP to XMPP,
          encode "'" as "\27").

4.3.  Instance-Specific Mapping

   The meaning of a resourcepart in XMPP (i.e., the portion of a JID
   after the slash character, such as "foo" in "user@example.com/foo")
   matches that of a Globally Routable User Agent URI (GRUU) in SIP
   [RFC5627].  In both cases, these constructs identify a particular
   device associated with the bare JID ("localpart@domainpart") of an
   XMPP entity or with the Address of Record (AOR) of a SIP entity.



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   Therefore, it is reasonable to map the value of a "gr" URI parameter
   to an XMPP resource part, and vice-versa.

   Note that the "gr" URI parameter in SIP can contain only characters
   from the ASCII range, whereas an XMPP resourcepart can contain nearly
   any Unicode character [UNICODE].  Therefore Unicode characters
   outside the ASCII range need to be mapped to characters in the ASCII
   range, as described below.

4.4.  SIP 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 any percent-encoded strings ("%hexhex") to percent-
       decoded octets.
   4.  Treat result as a UTF-8 string.
   5.  Translate "&" to "\26", "'" to "\27", and "/" to "\2f"
       respectively in order to properly handle the characters
       disallowed in XMPP addresses but allowed in sip:/sips: URIs and
       im:/pres: URIs as shown in Table 1 above (this is consistent with
       [XEP-0106]).
   6.  Apply Nodeprep profile of Stringprep [RFC3454] or its replacement
       (see [RFC6122] and [I-D.ietf-xmpp-6122bis]) for canonicalization
       (OPTIONAL).
   7.  Recombine local part with mapped hostname to form a bare JID
       ("localpart@domainpart").
   8.  If the (SIP) address contained a "gr" URI parameter, append a
       slash character "/" and the "gr" value to the bare JID to form a
       full JID ("localpart@domainpart/resourcepart").

4.5.  XMPP to SIP

   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 localpart (mapping described in remaining
       steps), domainpart (hostname; mapping is out of scope), and
       resourcepart (specifier for particular device or connection, for
       which an OPTIONAL mapping is described below).
   2.  Apply Nodeprep profile of [RFC3454] or its replacement (see
       [RFC6122] and [I-D.ietf-xmpp-6122bis]) for canonicalization of
       the XMPP localpart (OPTIONAL).





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   3.  Translate "\26" to "&", "\27" to "'", and "\2f" to "/"
       respectively (this is consistent with [XEP-0106]).
   4.  Determine if the foreign domain supports im: and pres: URIs
       (discovered via [RFC2782] lookup as specified in [RFC6121]), else
       assume that the foreign domain supports sip:/sips: URIs.
   5.  If converting into im: or pres: URI, for each byte, if the byte
       is in the set (),.;[\] or is a UTF-8 character outside the ASCII
       range then percent-encode that byte to "%hexhex" format.  If
       converting into sip: or sips: URI, for each byte, if the byte is
       in the set #%[\]^`{|} or is a UTF-8 character outside the ASCII
       range then percent-encode that byte to "%hexhex" format.
   6.  Combine resulting local part with mapped hostname to form
       local@domain address.
   7.  Prepend with 'im:' scheme (for XMPP <message/> stanzas) or
       'pres:' scheme (for XMPP <presence/> stanzas) if foreign domain
       supports these, else prepend with 'sip:' or 'sips:' scheme
       according to local service policy.
   8.  If the XMPP address included a resourcepart and the destination
       URI scheme is 'sip:' or 'sips:', optionally append the slash
       character '/' and then append the resourcepart (making sure to
       percent-encode any UTF-8 characters outside the ASCII range) as
       the "gr" URI parameter.


5.  Error Condition Mapping

   SIP response codes are specified in [RFC3261] and XMPP error
   conditions are specified in [RFC6120].  Because there is no
   equivalent in XMPP for the provisional (1xx) and successful (2xx)
   response codes in SIP, mappings are provided only for the redirection
   (3xx), request failure (4xx), server failure (5xx), and glogal
   failure (6xx) codes.



















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5.1.  XMPP to SIP

   Table 8: Mapping of XMPP error conditions to SIP response codes

      +------------------------------+---------------------+
      |  XMPP Error Condition        |  SIP Response Code  |
      +------------------------------+---------------------+
      |  <bad-request/>              | 400                 |
      |  <conflict/>                 | 400                 |
      |  <feature-not-implemented/>  | 501                 |
      |  <forbidden/>                | 403                 |
      |  <gone/>                     | 410                 |
      |  <internal-server-error/>    | 500                 |
      |  <item-not-found/>           | 404                 |
      |  <jid-malformed/>            | 484                 |
      |  <not-acceptable/>           | 406                 |
      |  <not-allowed/>              | 405                 |
      |  <not-authorized/>           | 401                 |
      |  <recipient-unavailable/>    | 480                 |
      |  <redirect/>                 | 300                 |
      |  <registration-required/>    | 407                 |
      |  <remote-server-not-found/>  | 502                 |
      |  <remote-server-timeout/>    | 504                 |
      |  <resource-constraint/>      | 500                 |
      |  <service-unavailable/>      | 503                 |
      |  <subscription-required/>    | 407                 |
      |  <undefined-condition/>      | 400                 |
      |  <unexpected-request/>       | 491                 |
      +------------------------------+---------------------+

5.2.  SIP to XMPP

   The mapping of SIP response codes to XMPP error conditions SHOULD be
   as follows (note that XMPP does not include 100-series or 200-series
   response codes, only error conditions):

   Table 9: Mapping of SIP response codes to XMPP error conditions














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      +---------------------+------------------------------+
      |  SIP Response Code  |  XMPP Error Condition        |
      +---------------------+------------------------------+
      |  300                |  <redirect/>                 |
      |  301                |  <gone/>                     |
      |  302                |  <redirect/>                 |
      |  305                |  <redirect/>                 |
      |  380                |  <not-acceptable/>           |
      |  400                |  <bad-request/>              |
      |  401                |  <not-authorized/>           |
      |  402                |  see note [1]                |
      |  403                |  <forbidden/>                |
      |  404                |  <item-not-found/>           |
      |  405                |  <not-allowed/>              |
      |  406                |  <not-acceptable/>           |
      |  407                |  <registration-required/>    |
      |  408                |  <recipient-unavailable/>    |
      |  410                |  <gone/>                     |
      |  413                |  <bad-request/>              |
      |  414                |  <bad-request/>              |
      |  415                |  <bad-request/>              |
      |  416                |  <bad-request/>              |
      |  420                |  <bad-request/>              |
      |  421                |  <bad-request/>              |
      |  423                |  <bad-request/>              |
      |  480                |  <recipient-unavailable/>    |
      |  481                |  <item-not-found/>           |
      |  482                |  <not-acceptable/>           |
      |  483                |  <not-acceptable/>           |
      |  484                |  <jid-malformed/>            |
      |  485                |  <item-not-found/>           |
      |  486                |  <recipient-unavailable/>    |
      |  487                |  <recipient-unavailable/>    |
      |  488                |  <not-acceptable/>           |
      |  491                |  <unexpected-request/>       |
      |  493                |  <bad-request/>              |
      |  500                |  <internal-server-error/>    |
      |  501                |  <feature-not-implemented/>  |
      |  502                |  <remote-server-not-found/>  |
      |  503                |  <service-unavailable/>      |
      |  504                |  <remote-server-timeout/>    |
      |  505                |  <not-acceptable/>           |
      |  513                |  <bad-request/>              |
      |  600                |  <recipient-unavailable/>    |
      |  603                |  <recipient-unavailable/>    |
      |  604                |  <item-not-found/>           |
      |  606                |  <not-acceptable/>           |
      +---------------------+------------------------------+



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   1.  The XMPP <payment-required/> error condition was removed in
       [RFC6120].


6.  Security Considerations

   Detailed security considerations for SIP are given in [RFC3261] and
   for XMPP in [RFC6120].


7.  IANA Considerations

   This document requests no actions of IANA.


8.  References

8.1.  Normative References

   [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.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, January 2005.

   [RFC4395]  Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
              Registration Procedures for New URI Schemes", RFC 4395,
              February 2006.

   [RFC5627]  Rosenberg, J., "Obtaining and Using Globally Routable User
              Agent URIs (GRUUs) in the Session Initiation Protocol
              (SIP)", RFC 5627, October 2009.

   [RFC6120]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Core", RFC 6120, March 2011.

   [RFC6122]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Address Format", RFC 6122, March 2011.

   [UNICODE]  The Unicode Consortium, "The Unicode Standard, Version
              6.2", 2012,
              <http://www.unicode.org/versions/Unicode6.2.0/>.



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8.2.  Informative References

   [I-D.ietf-xmpp-6122bis]
              Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Address Format",
              draft-ietf-xmpp-6122bis-07 (work in progress), April 2013.

   [RFC2782]  Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
              specifying the location of services (DNS SRV)", RFC 2782,
              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.

   [RFC3454]  Hoffman, P. and M. Blanchet, "Preparation of
              Internationalized Strings ("STRINGPREP")", RFC 3454,
              December 2002.

   [RFC3856]  Rosenberg, J., "A Presence Event Package for the Session
              Initiation Protocol (SIP)", RFC 3856, August 2004.

   [RFC3859]  Peterson, J., "Common Profile for Presence (CPP)",
              RFC 3859, August 2004.

   [RFC3860]  Peterson, J., "Common Profile for Instant Messaging
              (CPIM)", RFC 3860, August 2004.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              October 2008.

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

   [XEP-0106]
              Saint-Andre, P. and J. Hildebrand, "JID Escaping", XSF
              XEP 0106, May 2005.


Appendix A.  Acknowledgements

   The authors wish to thank the following individuals for their
   feedback: Fabio Forno, Adrian Georgescu, Saul Ibarra, Markus Isomaki,
   Salvatore Loreto, Daniel-Constantin Mierla, Tory Patnoe, and Robert
   Sparks.





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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


   Avshalom Houri
   IBM
   Building 18/D, Kiryat Weizmann Science Park
   Rehovot  76123
   Israel

   Email: avshalom@il.ibm.com


   Joe Hildebrand
   Cisco Systems, Inc.
   1899 Wynkoop Street, Suite 600
   Denver, CO  80202
   USA

   Email: jhildebr@cisco.com























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