1. Introduction

1.1. Overview

   The Instant Messaging and Presence (IMPP) Working Group has defined
   an abstract framework for interoperability among instant messaging
   (IM) and presence systems that are compliant with [IMP-REQS].  This
   framework is commonly called Common Presence and Instant Messaging or
   "CPIM".  The CPIM family of specifications include a Common Profile
   for Instant Messaging [CPIM] (also called CPIM), a Common Profile for
   Presence [CPP], a CPIM Message Format [MSGFMT], and a Common Presence
   Information Data Format [PIDF].  (Note: To prevent confusion, Common
   Presence and Instant Messaging is referred to herein collectively as
   "the CPIM specifications", whereas the Common Profile for Instant
   Messaging is referred to as "CPIM".)

   This memo describes how the Extensible Messaging and Presence
   Protocol ([XMPP-CORE], [XMPP-IM]) maps to the abstract model
   contained in the CPIM specifications, mainly for the purpose of
   establishing gateways between XMPP services and non-XMPP services
   that conform to [IMP-REQS].  Such a gateway, referred to herein as an
   "XMPP-CPIM gateway", may be established to interpret the protocols of
   one service and translate them into the protocols of the other
   service.  We can visualize this relationship as follows:

     +-------------+        +-------------+        +------------+
     |             |        |             |        |            |
     |    XMPP     |        |  XMPP-CPIM  |        |  Non-XMPP  |
     |   Service   | <----> |   Gateway   | <----> |  Service   |
     |             |        |             |        |            |
     +-------------+        +-------------+        +------------+

   This memo defines a mapping for use by a gateway that translates
   between XMPP and a non-XMPP protocol via the CPIM specifications.
   Such a gateway is not an intermediate hop on a network of non-XMPP
   servers (whose native formats may or may not be defined by the CPIM
   specifications), but a dedicated translator between XMPP and a
   non-XMPP protocol, where the CPIM specifications define the common
   formats into which the protocols are translated for purposes of
   interworking.

   The mapping defined herein applies to instant messages and presence
   information that are not encrypted or signed for end-to-end security.
   For information about secure communications to or from an XMPP
   service through an XMPP-CPIM gateway, refer to [XMPP-E2E].

1.2. Terminology

   This memo inherits vocabulary defined in [IMP-MODEL].  Terms such as
   CLOSED, INSTANT INBOX, INSTANT MESSAGE, OPEN , PRESENCE SERVICE,
   PRESENTITY, SUBSCRIPTION, and WATCHER are used in the same meaning as
   defined therein.

   This memo also inherits vocabulary defined in [XMPP-CORE].  Terms
   such as ENTITY, NODE IDENTIFIER, DOMAIN IDENTIFIER, RESOURCE
   IDENTIFIER, MESSAGE STANZA, and PRESENCE STANZA are used in the same
   meaning as defined therein.

1.3. Conventions Used in this Document

   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
   [TERMS].