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Versions: 00 01 02 03 04 05 06 07 08 RFC 3863

Network Working Group                                         H. Sugano
INTERNET-DRAFT                                              S. Fujimoto
                                                                Fujitsu
                                                               G. Klyne
                                                 Baltimore Technologies
                                                             A. Bateman
                                                             VisionTech

Expires: April 2002                                        October 2001


                 CPIM Presence Information Data Format
                   <draft-ietf-impp-cpim-pidf-01.txt>

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.

   Please send comments to the authors or to the impp@iastate.edu
   discussion list.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This memo specifies CPIM Presence Information Data Format (PIDF) as a
   common presence data format for CPIM-compliant IM/Presence protocols.





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Table of Content

      1.     Introduction .........................................    3
      1.1.   Terminology and Conventions ..........................    3
      2.     Design Decisions .....................................    3
      2.1.   Minimal Model ........................................    3
      3.     Overall Presence Information Data Structure ..........    4
      3.1.   The 'application/cpim-pidf+xml' Content Type .........    5
      3.2.   Combining Multiple Presence Documents ................    5
      4.     XML-encoded Presence Data Format .....................    6
      4.1.   XML Format Definitions ...............................    6
      4.1.1. The <presence> element ...............................    6
      4.1.2. The <presentity> element .............................    6
      4.1.3. The <tuple> element ..................................    6
      4.1.4. The <status> element .................................    7
      4.1.5. The <value> element ..................................    7
      4.1.6. The <contact> element ................................    7
      4.1.7. The <note> element ...................................    7
      4.1.8. The <timestamp> element ..............................    8
      4.2.   Presence Information Extensibility ...................    8
      4.2.1. XML Namespaces Background ............................    8
      4.2.2. XML Namespaces In Presence Information ...............    9
      4.2.3. Handling Of Unrecognized Element Names ...............    9
      4.3.   Examples .............................................   10
      4.3.1. Default Namespace And No Extensions ..................   10
      4.3.2. Example Presence Information Extensions ..............   11
      4.3.3. Example Mandatory To Understand Extensions ...........   11
      4.4.   DTD ..................................................   12
      5.     Wrapping 'application/cpim-pidf+xml' Data ............   13
      5.1.   When Used With 'message/cpim' ........................   13
      5.1.1. The 'From' header ....................................   13
      5.1.2. The 'To' header ......................................   13
      5.1.3. The 'DateTime' header ................................   13
      5.1.4. The 'NS' header ......................................   14
      5.1.5. The 'Require' header .................................   14
      5.2.   When Used With 'multipart/mixed' .....................   14
      5.2.1. The 'Presence-Data-ID' header ........................   14
      5.3.   Examples .............................................   14
      6.     Security Considerations ..............................   15
      7.     IANA Considerations ..................................   16
      8.     References ...........................................   16
      9.     Author's Addresses ...................................   17
      10.     Full Copyright Statement ............................   18








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1.     Introduction

   The IMPP working group has been working to develop the Common Profile
   for Instant Messaging (CPIM) specifications to achieve
   interoperability of IM and Presence services between different
   protocol domains.  The the CPIM core document [CPIM] defines a set of
   common operations and their parameters to be supported by
   interworking IM/Presence protocols. The work on CPIM Message Format
   [CPIM-MSG] defines a common format for instant messages, which
   enables secure end-to-end IM exchange.

   This memo defines the CPIM Presence Information Data Format (PIDF) as
   a common presence data format for CPIM-compliant IM/Presence
   protocols.  Encoded in the common format, presence data can be
   securely transferred across the boundary of different protocol
   domains by utilizing digital signature and/or encryption.

1.1.   Terminology and Conventions

   This memos makes use of the vocabulary defined in the IMPP Model
   document [RFC2778]. Terms such as as CLOSED, INSTANT INBOX, INSTANT
   MESSAGE, OPEN, PRESENCE SERVICE, PRESENTITY, SUBSCRIPTION, and
   WATCHER are used in the same meaning as defined therein.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
   interpreted as described in RFC 2119 [34].

   [[[Editorial comments and questions about outstanding issues are
   provided in triple brackets like this.  These working comments should
   be resolved and removed prior to final publication.]]]


2.     Design Decisions

   We have adopted the IMPP Model and Requirements documents [RFC2778,
   RFC2779] as the starting point of our discussion. The two RFCs
   contains some statements about presence information, which can be
   regarded as a basic set of constraints for the format design.  Also,
   we took the minimalist approach to the design based on them. Starting
   from the minimal model, only the features that are necessary to solve
   particular problems were combined.


2.1.   Minimal Model

   This specification is based on the following minimal model and
   requirements.



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   (a) A presence data unit contains one or more PRESENCE TUPLES,
       where a PRESENCE TUPLE consists of a STATUS, an optional
       COMMUNICATION ADDRESS, and optional OTHER PRESENCE MARKUP.
       (RFC2778:3)

   (b) STATUS has at least the mutually-exclusive values OPEN and
       CLOSED, which have meaning for the acceptance of INSTANT
       MESSAGES, and may have meaning for other COMMUNICATION MEANS.
       There may be other values of STATUS that do not imply anything
       about INSTANT MESSAGE acceptance. These other values of STATUS
       may be combined with OPEN and CLOSED or they may be mutually-
       exclusive with those values. (RFC2778:3, RFC2779:4.4.1-3)

   (c) STATUS may consist of single or multiple values. (RFC2778:2.4)

   (d) There must be a means of extending the common presence format
       to represent additional information not included in the common
       format.  The extension and registration mechanisms must be
       defined for presence information schema, including new STATUS
       conditions and new forms for OTHER PRESENCE MARKUP. (RFC2779:
       3.1.4-5)

   (e) The common presence format MUST include a means to uniquely
       identify the PRESENTITY whose PRESENCE INFORMATION is reported.
       (RFC2779:3.1.2)

   (f) The common presence format must allow the source of the presence
       data (i.e. presentity) to utilize some security mechanism (e.g.
       digital signature or encryption) for the secure transportation
       of the data. (RFC2779:5.2.1,5.3.1,5.3.3)


3.     Overall Presence Information Data Structure

   This memo defines a new content type and header fields for a MIME
   entity containing CPIM presence data.

   The CPIM presence format uses XML (eXtensible Markup Language, [XML])
   as the syntactic framework for the presece data document because XML
   is an excellent framework to contain structured data such as presence
   information and inherently extensible. A new content type
   "application/cpim-pidf+xml" is defined for the XML-encoded presence
   documents.

   The XML-encoded presence document MAY be enclosed by a MIME entity of
   the content type "message/cpim", which is defined as the CPIM Message
   Format [CPIM-MSG].  One of the cases for which the "message/cpim"
   format is necessary is that the presence server gives the third party



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   signature to the presence document with some additional data.

   Note that the "application/cpim-pidf+xml" content itself can
   optionally be signed or encrypted by the source of this presence data
   using MIME security multiparts in conjunction with an appropriate
   security scheme.


3.1.   The 'application/cpim-pidf+xml' Content Type

   The MIME body of the content type "application/cpim-pidf+xml"
   includes the following information.

     o Presentity URL: specifies the "pres" URL of the presentity.
     o List of presence tuples
       - Status: OPEN/CLOSED for Instant Messaging or status for
           other communication means.
       - Communication address: communication means and contact
           address of this tuple. (optional)
       - Relative priority: numerial value specifying the priority
           of this communication address. (optional)
       - Timestamp: timestamp of the change of this tuple.(optional)
       - Human readable comment: free text memo about this tuple
           (optional)
     o Presentity human readable comment: free text memo about the
         presentity (optional).

   [[[ There were discussions on the IMPP mailing list about timestamp,
   priority, and human readable comment. For the timestamp and priority,
   it seems that we have reached a consensus. But, for human readable
   comment, more discussions will be needed. ]]]

   The content type "application/cpim-pidf+xml" MAY have a "charset"
   parameter to indicate the character set and its encoding used in the
   body.  If no "charset" is specified, the application MUST treat the
   body as "UTF-8" encoded.


3.2.   Combining Multiple Presence Documents

   If a presence service needs to combine multiple presence documents in
   a single notification message, the MIME multipart entity is used.
   The reason for using MIME multipart comes from an architectural
   consideration such that each component presence document may come
   from different sources and it might be secured with a MIME security
   mechanism by the presence source.

   For the purpose of combining multiple presence documents, the



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   "multipart/mixed" content type MUST be used.  Each part of the
   multipart entity itself SHOULD be an "application/cpim-pidf+xml" type
   MIME entity or a signed or encrypted MIME entity using the MIME
   security multiparts in conjunction with an appropriate security
   scheme.

   Each multipart SHOULD contain a Presence-Data-ID header field whose
   value is used by the watcher user agent to identify the
   corresnponding part of the entire presence data of the particular
   presentity.


4.     XML-encoded Presence Data Format

   This section defines an XML-encoded presence data format of the
   content type application/cpim-pidf+xml for presence payloads. A
   presence payload of this type is expected to be produced by the
   presentity (the source of the presence information) and transported
   to the watchers by the presence servers or gateways without any
   interpretation or modification.

4.1.   XML Format Definitions

   An application/cpim-pidf+xml object is a well formed XML document.

4.1.1. The <presence> element

   The root element of the 'application/cpim-pidf+xml' object is defined
   as <presence>.  This element contains one <presentity> element, one
   or more <tuple> elements, and an optional <note> element.

   The <presence> element SHOULD contain an 'xmlns' attribute to
   indicate the namespace of the version of the presence document.  The
   presence document compliant to this specification MUST have the
   namespace 'urn:ietf:params:cpim-presence:'.

4.1.2. The <presentity> element

   The <presentity> element MUST have an 'id' attribute and has no
   content.  The value of the 'id' attribute is the 'pres' URL of the
   publisher presentity of this presence information.

4.1.3. The <tuple> element

   The <tuple> element is used to carry a piece of presence information
   defined as PRESENCE TUPLE in RFC2778.  Thus, it contains a mandatory
   <status> element and optional <contact>, <note>, and <timestamp>
   elements.



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   The <tuple> element MUST contain an 'id' attribute which is used to
   distinguish this tuple from other tuples of the same presentity.  The
   value of 'id' attribute MUST be unique in a single presentity.

   The <contact> element is optional so as to allow a presentity to show
   its status hiding its communication address or to allow tuples not
   related to any communication means.

4.1.4. The <status> element

   The <status> element contains one or more <value> elements. It can
   have multiple status values at the same time.

4.1.5. The <value> element

   The <value> element contains a CDATA value and has optional 'type'
   and 'schema' attributes.  The 'type' attribute indicates the type of
   this value which restrict the range of the values in which the
   content CDATA value varies.   The 'schema' attribute is a URL
   pointing to the definition of the type and its possible values, which
   is usually a DTD.

   If the type attribute does not appear, the application MUST
   understand that the type is 'urn:ietf:params:cpim-presence:status-
   type:basic', i.e. the 'basic' type whose possible values are either
   "open" or "closed".  As defined in RFC 2778, "open" and "closed"
   stand for availability of receiving insatnt messages if the <tuple>
   is for an instant messaging address.  They also have meanings of
   general availability for other communication means. But, this memo
   does not specify them in detail.

   Also, this memo does not specify other value types such as
   'urn:ietf:params:cpim-presence:status-type:im'.  However, the
   'urn:ietf:params:cpim-presence:status-type:im' type will be defined
   later in another specification document.

4.1.6. The <contact> element

   The <contact> element contains a URL of the contact address.  It
   optionally has a 'priority' attribute, whose value means a relative
   priority of this contact address over the others.  The value of the
   attribute MUST be an integer ranged from 0 to 255 and the smaller
   integer means the higher priority.  If the 'priority' attribute is
   omitted, applications MUST understand that the contact address has
   the lowest priority.

4.1.7. The <note> element




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   The <note> element contains a CDATA value, which is usually used for
   a human readable comment.  A <note> element MAY appear as a child
   element of <presence> and as that of the <tuple> element.  In the
   former case, the comment is about the presentity and, in the latter
   case, the comment is regarding the particular tuple.

4.1.8. The <timestamp> element

   The <timestamp> element contains a CDATA value which is a string
   indicating the date and time of the status change of this tuple.  The
   value of this element MUST follow the IMPP datetime format
   [DateTime].


4.2.   Presence Information Extensibility

   The presence information extensibility framework is based on XML
   namespaces [XML-NS].

4.2.1. XML Namespaces Background

   All elements and some attributes are associated with a "namespace",
   which is in turn associated with a globally unique URI.  Any
   developer can introduce their own element names, avoiding conflict by
   choosing an appropriate namespace URI.

   Within the presence data, element or attribute names are associated
   with a particular namespace by a namespace prefix, which is a leading
   part of the name, followed by a colon (":"); e.g.

      <prefix:element-name ...> ... </prefix:element-name>

   Where, 'prefix' is the header name prefix, 'element-name' is a name
   which is scoped by the namespace associated with 'prefix'.  Note that
   the choice of 'prefix' is quite arbitrary;  it is the corresponding
   URI that defines the naming scope.  Two different prefixes associated
   with the same namespace URI refer to the same namespace.

   A default namespace can be declared for XML elements without a
   namespace prefix.  The default namespace does NOT apply to attribute
   names, but interpretation of an unprefixed attribute can be
   determined by the containing element.

   A namespace is identified by a URI.  In this usage, the URI is used
   simply as a globally unique identifier, and there is no requirement
   that it can be used to retrieve a web resource, or for any other
   purpose.  Any legal globally unique URI MAY be used to identify a
   namespace.  (By "globally unique", we mean constructed according to



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   some set of rules so that it is reasonable to expect that nobody else
   will use the same URI for a different purpose.)

   For further details, see the XML namespace specification [XML-NS].

4.2.2. XML Namespaces In Presence Information

   A URI used as a namespace identifier in presence information data
   MUST be a full absolute-URI, per RFC 2396 [URI].  (Relative URIs and
   URI- references containing fragment identifiers MUST NOT be used for
   this purpose.)

   The namespace URI for elements defined by this specification is a URN
   [URN], using the namespace identifier 'ietf' defined by [URN-NS-IETF]
   and extended by [URN-SUB-NS]:

     urn:ietf:params:cpim-presence:

   Thus, simple presence data might be thus:

       <impp:presence xmlns:impp="urn:ietf:params:cpim-presence:">
         <impp:presentity id="pres:shingo@jp.fujitsu.com">
         <impp:tuple id="mobile-phone">
           <impp:status>
             <impp:value>open</impp:value>
           </impp:status>
           <impp:contact priority="9">tel:09012345678</impp:contact>
         </impp:tuple>
       </impp:presence>

   or, using a default XML namespace:

       <presence xmlns="urn:ietf:params:cpim-presence:">
         <presentity id="pres:shingo@jp.fujitsu.com">
         <tuple id="mobile-phone">
           <status>
             <value>open</value>
           </status>
           <contact priority="9">tel:09012345678</contact>
         </tuple>
       </presence>


4.2.3. Handling Of Unrecognized Element Names

   The default rule is that any element with an unrecognized name is
   ignored (i.e. having an unrecognized namespace URI, or an
   unrecognized local name within that namespace).  This includes all of



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   the element content, even if it appears to use recognized names.

   It may be that some extensions must be understood in order for the
   presence information to be properly understood.  In such cases, the
   element name is qualified with a mustUnderstand='YES' attribute,
   which attribute name is associated with the CPIM presence namespace.

     NOTE:  a mustUnderstand='YES' attribute within an element that is
     being ignored is itself ignored.  The writer of nested mandatory-
     to-understand information is responsible for ensuring that any
     enclosing element is also labelled with a mustUnderstand='YES'
     attribute, if necessary.

   This specification defines elsewhere the elements within the
   'urn:ietf:params:cpim-presence:' namespace that MUST be generated
   and/or recognized in CPIM presence data.  Processors MUST handle
   these as described here, even if they do not carry a mustUnderstand
   attribute.

   If an agent receives presence information containing an unrecognized
   element with a mustUnderstand='YES' attribute, it should treat the
   entire presence information as unrecognized and not attempt to
   process it.


4.3.   Examples

4.3.1. Default Namespace And No Extensions

   <presence xmlns="urn:ietf:params:cpim-presence:">
     <presentity id="pres:shingo@jp.fujitsu.com"/>
     <tuple id="mobile-im">
       <status>
         <value>OPEN</value>
         <value
           type="urn:ietf:params:cpim-presence:status-type:im">BUSY</value>
         <value
           type="urn:example-com:cpim-status-type:location"
           schema="http://www.example.com/impp/location.dtd">HOME</value>
       </status>
       <contact priority="2">im:shingo@mobilecarrier.ne.jp</contact>
       <note>Don't Disturb Please!</note>
       <timestamp>2001-10-27T16:49:29Z</timestamp>
     </tuple>
     <tuple id="email">
       <status>
         <value>OPEN</value>
       </status>



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       <contact priority="1">mailto:shingo@jp.fujitsu.com</contact>
     </tuple>
     <note>I'll be in Tokyo tomorrow</note>
   </presence>


4.3.2. Example Presence Information Extensions

   <impp:presence xmlns:impp="urn:ietf:params:cpim-presence:"
                  xmlns:myex="http://id.mycompany.com/cpim-presence/">
     <impp:presentity id="pres:shingo@jp.fujitsu.com">
     <myex:mytag>My extended presentity information</myex:mytag>

     <impp:tuple id="mobile-phone">
       <impp:status>
         <impp:value>open</impp:value>
       </impp:status>
       <myex:mytupleelement>Extended value in tuple</myex:mytupleelement>
       <impp:contact priority="9">tel:09012345678</impp:contact>
     </impp:tuple>
     <impp:tuple id="mobile-im">
       <impp:status>
         <impp:value>open</impp:value>
       </impp:status>
       <impp:contact priority="1">im:shingo@mobilecarrier.ne.jp</impp:contact>
     </impp:tuple>

   </impp:presence>

4.3.3. Example Mandatory To Understand Extensions

   <impp:presence xmlns:impp="urn:iana:impp:presence:"
                  xmlns:myex="http://id.mycompany.com/cpim-presence/">
     <impp:presentity id="pres:shingo@jp.fujitsu.com">
     <myex:mytag>My extended presentity information</myex:mytag>

     <impp:tuple id="mobile-phone">
       <impp:status>
         <impp:value>open</impp:value>
       </impp:status>
       <myex:complexExtension impp:mustUnderstand='YES'>
         <myex:ex1 impp:mustUnderstand='YES'>val1</myex:ex1>
         <myex:ex2>val2</myex:ex2>
       </myex:mandatoryExtension>
       <impp:contact priority="9">tel:09012345678</impp:contact>
     </impp:tuple>

   </impp:presence>



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   Here, <myex:complexExtension>, <myex:ex1> must be understood, but
   <myex:mytag> and <myex:ex2> may be ignored if they are not
   recognized.


4.4.   DTD

   Data Type Definition of the application/cpim-pidf+xml format.

   <!ENTITY % URL         "CDATA">
   <!ENTITY % URI         "CDATA">
   <!ENTITY % TUPLEID     "CDATA">
   <!ENTITY % DATETIME    "CDATA">
   <!ENTITY % VALUETYPE   "CDATA">
   <!ENTITY % PRIORITY    "CDATA">
   <!ENTITY % NOTE        "CDATA">

   <!ELEMENT presence (presentity,(tuple+),note?)>
   <!ATTLIST presence
             xmlns     %URI;   "urn:ietf:params:cpim-presence:"
   >

   <!ELEMENT presentity EMPTY>
   <!ATTLIST presentity
             id   %URL;          #REQUIRED
   >

   <!ELEMENT tuple (status,contact?,note?,timestamp?)>
   <!ATTLIST tuple
             id   %TUPLEID;      #REQUIRED
   >

   <!ELEMENT status (value+)>
   <!ELEMENT value CDATA>
   <!ATTLIST value
             type %VALUETYPE;
                  "urn:ietf:params:cpim-presence:status-type:basic"
             schema %URI;        #IMPLIED
   >

   <!ELEMENT contact %URL;>
   <!ATTLIST contact
             priority %PRIORITY; #IMPLIED
   >

   <!ELEMENT note %NOTE;>

   <!ELEMENT timestamp %DATETIME;>



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5.     Wrapping 'application/cpim-pidf+xml' Data

   [[[ A part of this section may contain what has not yet agreed upon
   in the IMPP group.  Futher discussions are needed. ]]]

   As stated in Section 3, an 'application/cpim-pidf+xml' document MAY
   be wrapped by a 'message/cpim' message [CPIM-MSG].  It MAY also be a
   part of a MIME multipart entity.  This section specifies how the
   'application/cpim-pidf+xml' document can be packed in another MIME
   entity.

5.1.   When Used With 'message/cpim'

   In order to use the CPIM Message Format, headers needed for this
   usage must be defined [CPIM-MSG].  Among the headers defined by the
   CPIM message format document, the following headers MAY be used to
   convey the presence information.  The default namespace and namespace
   prefix implicitly defined are same as defined in the 'message/cpim'
   specification document.

5.1.1. The 'From' header

   The 'From' header contains the address (pres: URL) of the presentity
   as the publisher of the contained presence information. Any
   application compliant to this specification MUST recognize the 'From'
   header.

   This use of 'From' may be considered redundant in the presence of
   <presentity> element in the presence document.  This header is needed
   when the presence server explicitly states the publisher regardless
   of the content of presence documents.


5.1.2. The 'To' header

   The 'To' header contains the address (pres: URL) of the watcher as
   the target of the NOTIFY message containing this presence document.
   Any application compliant to this specification MUST recognize the
   'To' header.

5.1.3. The 'DateTime' header

   The 'DateTime' header contains a character string of the format
   defined as IMPP datetime format [DateTime].  This value indicates the
   date and time at which the content part is created.  The 'DateTime'
   header MUST be present as a 'message/cpim' metadata header if the
   message contains an 'application/cpim-pidf+xml' object.  It MUST also
   be recognized by any application compliant to this specification.



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5.1.4. The 'NS' header

   The "NS" header is used to declare a local namespace prefix as
   defined by [CPIM-MSG]. Any application compliant to this
   specification MUST recognize the 'NS' header.

5.1.5. The 'Require' header

   The "Require" header is used to specify a header or feature that must
   be implemented by the receiver, as defined by [CPIM-MSG]. Any
   application compliant to this specification MUST recognize the
   'Require' header.


5.2.   When Used With 'multipart/mixed'

   When multiple presence documents are combined within a simple
   notification message, the 'multipart/mixed' content type MUST be
   used.  Each multipart SHOULD contain a 'Presence-Data-ID' header
   defined as follows.

5.2.1. The 'Presence-Data-ID' header

   The 'Presence-Data-ID' header contains the label for the unit of
   update.  This header will be used for indicating the part is
   replacement of the part which contained in previous NOTIFICATION with
   same 'Presence-Data-ID' value.


5.3.   Examples

   The following example is the message/cpim object containing two
   presence payload.  It is supposed that the first block is published
   by a PC and the second block is published by a mobile phone, and the
   second block has caused the notification message conveying this
   multipart content.


     Content-Type: message/cpim

     From: pres:shingo@jp.fujitsu.com
     To: pres:suga@flab.fujitsu.co.jp
     DateTime: 2001-06-01T08:35:44+09:00

     Content-Type: multipart/mixed; boundary="PRESENCE-BLOCKS"

     --PRESENCE-BLOCKS
     Content-Type: application/cpim-pidf+xml



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     Presence-Data-ID: part1

     <presence xmlns="urn:ietf:params:cpim-presence:">
       <presentity id="pres:shingo@jp.fujitsu.com">
       <tuple id="pc-im">
         <status>
           <value>OPEN</value>
           <value
             type="urn:ietf:params:cpim-presence:status-type:im">AWAY</value>
         </status>
         <contact priority="2">im:shingo@jp.fujitsu.com</contact>
         <note>Boss Meeting</note>
       </tuple>
       <tuple id="email">
         <status>
           <value>OPEN</value>
         </status>
         <contact priority="1">mailto:shingo@jp.fujitsu.com</contact>
       </tuple>
     </presence>
     --PRESENCE-BLOCKS
     Content-Type: application/cpim-pidf+xml
     Presence-Data-ID: part2

     <presence xmlns="urn:ietf:params:cpim-presence:">
       <presentity id="pres:shingo@jp.fujitsu.com">
       <tuple id="mobile-phone">
         <status>
           <value>OPEN</value>
         </status>
         <contact priority="9">tel:09012345678</contact>
       </tuple>
       <tuple id="mobile-im">
         <status>
           <value>OPEN</value>
           <value
             type="urn:ietf:params:cpim-presence:status-type:location"
             schema="http://www.example.com/impp/location.dtd">HOME</value>
         </status>
         <contact priority="2">im:shingo@mobilecarrier.ne.jp</contact>
       </tuple>
     </presence>
     --PRESENCE-BLOCKS--


6.     Security Considerations

   The proposed format for conveying presence information is so designed



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   that it could be adaptable in circumstances under various security
   requirements.

   As a typical case, a user publishing his/her presence information may
   want to sign the data to prevent from being corrupted or tampered.
   This will ensure the integrity of presence information in an end-to-
   end manner.  This proposal enables it by allowing MIME multipart
   security framework, such as usage of the multipart/signed data type.

   Another possible scenario is that of third party signing.  If the
   computing power of the terminal device of the publishing user is
   restricted, the server side signing would be sometimes desirable to
   enhance the level of security in distributing presence information.
   This enables to prevent from so-called "the man in the middle"
   attacks when the presence notifications are distributed through the
   proxies or gateways.

7.     IANA Considerations

   [[[Will need a registration template per [URN-SUB-NS], for the URN
   sub-namespace 'urn:ietf:params:cpim-presence:']]]


8.     References

   [CPIM] D. Crocker et al., "A Common Profile for Instant Messaging
   (CPIM)", draft-ietf-impp-cpim-01.txt, Work in Progress. (Temporarily
   Expired)

   [CPIM-MSG] D. Atkins and G. Klyne, "Common Presence and Instant
   Messaging Message Format", draft-ietf-impp-cpim-msgfmt-03.txt,
   Work in Progress.

   [RFC2778] M. Day, J. Rosenberg, H. Sugano, "A Model for Presence and
   Instant Messaging", RFC 2778, February 2000.

   [RFC2779] M. Day, S. Aggarwal, G. Mohr, and J. Vincent, "Instant
   Messaging / Presence Protocol Requirements", RFC 2779, February 2000.

   [XML] T. Bray, J. Paoli, C. Sperberg-McQueen and E. Maler,
   "Extensible Markup Language (XML) 1.0 (Second Edition)",
   W3C Recommendation, October 2000,
   <http://www.w3.org/TR/2000/REC-xml-20001006>

   [MIME] Multipurpose Internet Mail Extensions.  See RFC 822, RFC 2045,
   RFC 2046, RFC 2047, RFC 2048, and RFC 2049.

   [DateTime] G. Klyne and C.Newman, "Date and Time on the Internet:



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   Timestamps", draft-ietf-impp-datetime-04.txt, Work in Progress.

   [XML-NS] Tim Bray, Dave Hollander, and Andrew Layman "Namespaces in
   XML", W3C recommendation: xml-names, 14 January 1999,
   <http://www.w3.org/TR/REC-xml-names>

   [URI] T. Berners-Lee, R.T.Fielding and L. Masinter, "Uniform
   Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998.

   [URN] R. Moats, "URN Syntax", RFC 2141, May 1997.

   [URN-NS-IETF]  R. Moats, "A URN Namespace for IETF Documents", RFC
   2648, August 1999.

   [URN-SUB-NS]  M. Mealling, L. Masinter, T. Hardie and G. Klyne,
   "An IETF URN Sub-namespace for Registered Protocol Parameters",
   Internet-Draft draft-mealling-iana-urn-01, Work in Progress.



9.     Author's Addresses

   Hiroyasu Sugano
   Fujitsu Laboratories Ltd.
   64, Nishiwaki
   Ohkubo-cho
   Akashi 674
   Japan
   E-mail: sugano.h@jp.fujitsu.com

   Shingo Fujimoto
   Fujitsu Laboratories Ltd.
   64, Nishiwaki
   Ohkubo-cho
   Akashi 674
   Japan
   E-mail: shingo_fujimoto@jp.fujitsu.com

   Graham Klyne
   Baltimore Technologies - Content Security Group,
   1310 Waterside,
   Arlington Business Park
   Theale
   Reading, RG7 4SA
   United Kingdom.
   Telephone: +44 118 903 8000
   Facsimile: +44 118 903 9000
   E-mail: GK@ACM.ORG



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   Adrian Bateman
   VisionTech Limited
   Colton, Staffordshire, WS15 3LD
   United Kingdom
   E-mail: bateman@acm.org


10.     Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
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   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

















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