Internet DRAFT - draft-isomaki-simple-xcap-pidf-manipulation-usage
draft-isomaki-simple-xcap-pidf-manipulation-usage
SIMPLE WG M. Isomaki
Internet-Draft Nokia Research Center
Expires: August 6, 2004 E. Leppanen
Nokia
February 6, 2004
An Extensible Markup Language (XML) Configuration Access Protocol
(XCAP) Usage for Manipulating Presence Document Contents
draft-isomaki-simple-xcap-pidf-manipulation-usage-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 6, 2004.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document describes a usage of the Extensible Markup Language
(XML) Configuration Access Protocol (XCAP) for manipulating the
contents of Presence Information Data Format (PIDF) based presence
document. It is mainly intended to be used in Session Initiation
Protocol (SIP) based presence systems, where the Event State
Compositor can use the XCAP-manipulated presence document as one of
the inputs based on which it builds the overall presence state for
the presentity.
Isomaki & Leppanen Expires August 6, 2004 [Page 1]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Relationship with presence state published using SIP
PUBLISH . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Application Unique ID . . . . . . . . . . . . . . . . . . . 5
5. Structure of Published Presence Information . . . . . . . . 5
6. Computed Data . . . . . . . . . . . . . . . . . . . . . . . 6
7. Additional Constraints . . . . . . . . . . . . . . . . . . . 6
8. Naming Conventions . . . . . . . . . . . . . . . . . . . . . 6
9. Authorization Policies . . . . . . . . . . . . . . . . . . . 6
10. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 6
11. Example Document . . . . . . . . . . . . . . . . . . . . . . 6
12. Security Considerations . . . . . . . . . . . . . . . . . . 7
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7
13.1 XCAP Application Usage ID . . . . . . . . . . . . . . . . . 8
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
Normative References . . . . . . . . . . . . . . . . . . . . 8
Informative References . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 9
Intellectual Property and Copyright Statements . . . . . . . 10
Isomaki & Leppanen Expires August 6, 2004 [Page 2]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
1. Introduction
The Session Initiation Protocol (SIP) for Instant Messaging and
Presence (SIMPLE) specifications allow a user, called a watcher, to
subscribe to another user, called a presentity [6], in order to learn
their presence information [7].
A SIP based mechanism, SIP PUBLISH method, has been defined for
publishing presence state [13]. However, SIP PUBLISH has a limited
scope and does not address all the requirements for setting presence
state. First, it only allows a single Presence User Agent (PUA) to
publish its view of the presence state, independently of and without
the possibility to learn about the states set by other PUAs. Since
each PUA is typically tied to a single physical device, this means
that it is hard to set device independent presence state using SIP
PUBLISH. Second, SIP PUBLISH creates a soft state which expires after
the negotiated lifetime unless it is refreshed. This makes it
unsuitable for setting state that should prevail even without active
refreshing. There are several use cases where setting of permanent
presence state that can be manipulated independent of any device is
needed. For instance presentity's e-mail (mailto: URI) and WWW
homepage (http: URI) address are this kind of information. Similarly
a user might want to set information, such as note, that should
constitute his presence in the absence of any active publications,
i.e. serve as a sort of default presence state. SIMPLE based presence
systems thus require a mechanism to complement SIP PUBLISH in order
to address these use cases.
XML Configuration Access Protocol (XCAP) [2] allows a client to read,
write and modify application configuration data, stored in XML format
on a server. The data has no expiration time, so it must be
explicitly inserted and deleted. The protocol allows multiple clients
to manipulate the data, provided that they are authorized to do so.
XCAP is already used in SIMPLE based presence systems for
manipulation of presence lists and presence authorization policies.
This makes XCAP an ideal choice for doing device independent presence
document manipulation.
This document defines an XML Configuration Access Protocol (XCAP)
application usage for manipulating the contents of presence document.
CPIM PIDF [3] is used as the presence document format, since event
state compositor already has to support it, as it is used in SIP
PUBLISH.
Section 3 describes in more detail how the presence document
manipulated with XCAP is related to soft state publishing done with
SIP PUBLISH.
Isomaki & Leppanen Expires August 6, 2004 [Page 3]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
XCAP requires application usages to standardize several pieces of
information, including an application unique ID (AUID), and an XML
schema for the manipulated data. These are specified starting from
the Section 4.
2. Conventions
In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED',
'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY',
and 'OPTIONAL' are to be interpreted as described in RFC 2119 [1]
and indicate requirement levels for compliant implementations.
Comprehensive terminology of presence and event state publishing is
provided in [13].
3. Relationship with presence state published using SIP PUBLISH
The framework for publishing presence state is introduced in [12]. A
central part of the framework is the event state compositor element
whose function is to compose presence information received from
serveral sources.
The presence state manipulated with XCAP can be seen as one of the
information sources for the compositor to be combined with the soft
state information published using SIP PUBLISH. This is illustrated in
the figure below. It is expected that in the normal case there can be
several PUAs publishing their separate views, but only single XCAP
manipulated presence document.
Isomaki & Leppanen Expires August 6, 2004 [Page 4]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
+---------------+ +------------+
| Event State | | Presence |--> SIP SUBSCRIBE
| Compositor +---------+ Agent |<-- SIP NOTIFY
| | | (PA) |
+-------+-------+ +------------+
^ ^ ^
| | |
| | | +---------------+
+--------+ | +-------| XCAP server |
| | +-------+-------+
| | ^ ^
| SIP Publish | | XCAP |
| | | |
+--+--+ +--+--+ +-------+ +-------+
| PUA | | PUA | | XCAP | | XCAP |
| | | | | client| | client|
+-----+ +-----+ +-------+ +-------+
Figure 1: Framework for Presence Publishing and Event State
Composition
How the compositor combines the hard state information with the soft
state information to form a coherent presence document is entirely a
matter of local policy, and is beyond the scope of this document.
Also the exact protocol interface between XCAP server and the event
state compositor is not specified here. The obvious requirement is
that such interface exists, and that the presentity indeed has an
XCAP server supporting the usage defined in this specification
provisioned for him.
4. Application Unique ID
XCAP requires application usages to define a unique application usage
ID (AUID) in either the IETF tree or a vendor tree. This
specification defines the 'pidf-manipulation' AUID within the IETF
tree, via the IANA registration in the Section 13.
5. Structure of Published Presence Information
The XML [5] format of the presence information (PIDF) is defined in
[3] and its extensions. The PIDF defines the presence information to
consist of the root element 'presence' including 'tuples' which
contain a mandatory status element, a communication mean specific
presence attribute and other markups. Additionally, the presence
information can contain other presentity level information outside
tuples.
Isomaki & Leppanen Expires August 6, 2004 [Page 5]
The namespace URI for PIDF is defined in [3].
6. Computed Data
There are no computed data on the document beyond those described in
the schema.
7. Additional Constraints
There are no constraints on the document beyond those described in
the XML schemas and [3].
8. Naming Conventions
There are no naming conventions beyond the possible conventions
defined in [3] that need to be defined for this application usage.
9. Authorization Policies
This application usage does not modify the default XCAP authorization
policy, which allows only a user (owner) to read, write or modify
their own documents. A server can allow privileged users to modify
documents that they don't own, but the establishment and indication
of such policies is outside the scope of this document.
10. XML Schema
The XML schema definition for the presence information can be found
from [3] and its extensions.
11. Example Document
The following example document illustrates the situation where the
(human) presentity has left for vacation, and before that has set his
presence state such that he is only available via cellular phone and
e-mail. In the absence of any published soft state information, this
would be the sole input to the compositor forming the presence
document. The example document contain PIDF extensions specified in
[10] and [11].
<?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:cpim-pidf"
xmlns:es="urn:ietf:params:xml:ns:pidf:rpid-status"
xmlns:et="urn:ietf:params:xml:ns:pidf:rpid-tuple"
xmlns:ci="urn:ietf:params:xml:ns:pidf:cipid"
entity="pres:someone@example.com">
<tuple id="18x765">
<et:type>presentity</et:type>
Isomaki & Leppanen Expires August 6, 2004 [Page 6]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
<status>
<basic>open</basic>
<es:activity>Vacation</ep:activity>
</status>
<timestamp>2004-02-06T16:49:29Z</timestamp>
<note>I'm available only by e-mail and GSM phone.</note>
<ci:homepage>http://www.example.com/~someone</ci:homepage>
</tuple>
<tuple id="8eg92m">
<et:class>auth-1</et:class>
<et:type>service</et:type>
<status>
<basic>open</basic>
<es:idle/>
</status>
<note>cellphone</note>
<contact priority="0.5">tel:+358506767</contact>
</tuple>
<tuple id="8eg92n">
<et:class>auth-1</et:class>
<et:type>service</et:type>
<status>
<basic>open</basic>
<es:idle/>
</status>
<note>I'm reading mail a couple of times a week</note>
<contact priority="1.0">mailto:someone@example.com</contact>
</tuple>
</presence>
12. Security Considerations
The configuration information defined by this application usage is
particularly sensitive. It represents the set of presence information
which is delivered to watchers according to specific authorization
policies. As a result, clients SHOULD use TLS when contacting servers
in order to fetch this information. Also if the server delivers
presence information using the XCAP protocol it must be done
according to the defined authorization policy.
13. IANA Considerations
There are an IANA consideration associated with this specification.
Isomaki & Leppanen Expires August 6, 2004 [Page 7]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
13.1 XCAP Application Usage ID
This section registers a new XCAP Application Usage ID (AUID)
according to the IANA procedures defined in [2].
Name of the AUID: pidf-manipulation
Description: Pidf-manipulation application usage defines how XCAP is
used to manipulate the contents of presence documents in Session
Initiation Protocol (SIP) based presence systems.
14. Acknowledgements
The authors would like to thank Jonathan Rosenberg, Aki Niemi,
Krisztian Kiss and Jose Costa-Requena for their comments.
Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)",
draft-rosenberg-simple-xcap-01 (work in progress), October 2003.
[3] Sugano, H., "CPIM presence information data format",
draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003.
Informative References
[4] Mealling, M., "The IETF XML Registry",
draft-mealling-iana-xmlns-registry-05 (work in progress), June
2002.
[5] Bray, T., "Extensible Markup Language (XML) 1.0 (Second
edition)", W3C REC REC-xml-20001006, October 2000.
[6] Day, M., "A model for presence and instant messaging", RFC
2778, February 2000.
[7] Rosenberg, J., "Session Initiation Protocol (SIP) Extensions
for Presence", draft-ietf-simple-presence-10.txt (work in
progress), January 2003.
[8] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002.
[9] Peterson, J., "Common profile for presence (CPP)",
Isomaki & Leppanen Expires August 6, 2004 [Page 8]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
draft-ietf-impp-pres-03.txt (work in progress), May 2003.
[10] Schulzrinne, H., "RPID -- Rich Presence Information Data
Format", draft-ietf-simple-rpid-00.txt (work in progress),
July 2003.
[11] Schulzrinne, H., "CIPID: Contact Information in Presence
Information Data Format", draft-ietf-simple-cipid-00.txt (work
in progress), August 2003.
[12] Campbell, B., "SIMPLE Presence Publication Requirements",
draft-ietf-simple-publish-reqs-00 (work in progress), February
2003.
[13] Niemi, A., "Session Initiation Protocol (SIP) Extension for
Event State Publication", draft-ietf-sip-publish-02.txt (work
in progress), January 2004.
[14] Rosenberg, J., "A Session Initiation Protocol (SIP) Event
Package for Modification Events for the Extensible Markup
Language (XML) Configuration Access Protocol (XCAP) Managed
Documents", draft-rosenberg-simple-xcap-package-00 (work in
progress), May 2003.
Authors' Addresses
Markus Isomaki
Nokia Research Center
Itamerenkatu 11-13
00180 Helsinki
Finland
Phone:
EMail: markus.isomaki@nokia.com
Eva Leppanen
Nokia
P.O BOX 785
Tampere
Finland
Phone:
EMail: eva-maria.leppanen@nokia.com
Isomaki & Leppanen Expires August 6, 2004 [Page 9]
Internet-Draft XCAP Usage for Manipulating Presence Document 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. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Full Copyright Statement
Copyright (C) The Internet Society (2004). 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
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
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 assignees.
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
Isomaki & Leppanen Expires August 6, 2004 [Page 10]
Internet-Draft XCAP Usage for Manipulating Presence Document February 2004
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Isomaki & Leppanen Expires August 6, 2004 [Page 11]
