Internet DRAFT - draft-isomaki-simple-xcap-publish-usage
draft-isomaki-simple-xcap-publish-usage
SIMPLE WG M. Isomaki
Internet-Draft Nokia Research Center
Expires: April 2, 2004 E. Leppanen
Nokia
October 3, 2003
An Extensible Markup Language (XML) Configuraion Access Protocol
(XCAP) Usage for Publishing Presence Information
draft-isomaki-simple-xcap-publish-usage-00
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document describes a usage of the Extensible Markup Language
(XML) Configuration Access Protocol (XCAP) for publishers for
manipulating the hard state type of presence information within
SIMPLE presence publication framework.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Application Unique ID . . . . . . . . . . . . . . . . . . . 5
5. Structure of Published Presence Information . . . . . . . . 5
6. Computed Data . . . . . . . . . . . . . . . . . . . . . . . 5
7. Additional Constraints . . . . . . . . . . . . . . . . . . . 5
8. Naming Conventions . . . . . . . . . . . . . . . . . . . . . 5
9. Authorization Policies . . . . . . . . . . . . . . . . . . . 5
10. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 5
11. Example Document . . . . . . . . . . . . . . . . . . . . . . 6
12. Security Considerations . . . . . . . . . . . . . . . . . . 7
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7
13.1 XCAP Application Usage ID . . . . . . . . . . . . . . . . . 7
14. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 7
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
Normative References . . . . . . . . . . . . . . . . . . . . 8
Informative References . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 9
Intellectual Property and Copyright Statements . . . . . . . 10
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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].
The presence information is published by the user, called a
publisher. The presence server (PS) and presence agent (PA) have
access to the stored presence information. A SIP based mechanism has
been specified for publishing soft state type of presence information
[13]. However, there is also a need to manage such presence
information which neither requires refreshing nor needs definition of
the expiry time, e.g., the presence information of a closed
communication mean or some other more stabile information. Examples
include for instance presentity's e-mail or homepage address. This
kind of information is normally managed only when there is a need to
change the content. Such information is called hard state type of
presence information in this document.
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. It is possible to manipulate the
same data by multiple clients. With these properties XCAP fulfills
the requirements of hard state information publishing. Another
advantage is that XCAP is used in SIP-based presence systems also for
manipulation of presence lists and presence authorization policies.
This document defines an XML Configuration Access Protocol (XCAP)
application usage for manipulating hard state type of presence
information. CPIM PIDF [3] presence document format, which is used
for soft state information, is reused for hard state presence in
order to make the combination of different types of information
easier.
Section 3 introduces a framework how XCAP-based hard state presence
information publishing is related to soft state publishing done with
SIP.
XCAP requires application usages to standardize several pieces of
information, including an application unique ID (AUID), an XML
schema, and various other information. These pieces of information
are specified starting from the Section 4.
2. Conventions
In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED',
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'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. Framework
The framework for publishing presence state is introduced in [12]. A
central part of the framework is the event state compositor element
which function is to compose presence information received from
serveral sources.
The hard state information can be seen as one of the information
sources for the compositor to be combined with the soft state
information published using SIP PUBLISH [13]. This is illustrated in
the figure below. In order to make the combination easier, hard state
information uses the same format as soft state information, namely
CPIM PIDF and any of its extensions.
+---------------+ +------------+
| Event State | | Presence |--> SIP Subscribe
| Compositor +---------+ Agent |<-- SIP Notify
| | | (PA) |
+-------+-------+ +------------+
|
|
| +---------------+
+--------------^-------------| XCAP server |
| | +-------+-------+
| | ^
| SIP Publish | | XCAP Publish
| | |
+--+--+ +--+--+ +--------+--------------+
| PUA | | PUA | | XCAP presence-publish |
| | | | | client |
+-----+ +-----+ +-----------------------+
Figure 1: Framework for Publishing
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.
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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 'presence-publish' 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.
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 (a publisher) 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. At the time of writing this draft the
following extensions have been specified: [10] and [11].
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11. Example Document
The following example document defines the default state of the
presentity's presence information. 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">
<note>I'm available only by e-mail.</note>
<ci:homepage>http://www.example.com/~someone</ci:homepage>
<tuple id="7c8dqui">
<et:class>assistant</et:class>
<et:type>presentity</et:type>
<status>
<basic>open</basic>
<contact>sip:secretary@example.com</contact>
<es:relationship>assistant</ep:relationship>
</status>
<note>Please contact my secretary.</note>
</tuple>
<tuple id="18x765">
<et:type>presentity</et:type>
<status>
<basic></basic>
<es:activity>Vacation</ep:activity>
<es:placetype until="2003-11-27T17:30:00Z">home</ep:placetype>
<es:privacy>quiet</ep:privacy>
</status>
<timestamp>2001-10-27T16:49:29Z</timestamp>
</tuple>
<tuple id="35bs9r">
<et:class>phone</et:class>
<et:type>device</et:type>
<status>
<basic>closed</basic>
</status>
<timestamp>2001-10-27T16:49:29Z</timestamp>
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</tuple>
<tuple id="8eg92n">
<et:class>mail</et:class>
<et:type>device</et:type>
<status>
<basic>open</basic>
<es:idle/>
</status>
<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.
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: presence-publish
Description: A presence-publish application is a usage of the publish
framework for managing hard state type of presence information using
XCAP.
14. Open Issues
Publishing of external content: how to publish external content
(e.g., an icon) referenced from PIDF in case of the XCAP based
publishing? Is the content transported separately from the PIDF
formatted document so that the PIDF includes only a reference to the
separately transported content and the compositor is capable for
linking the information together? This might require that the
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compositor is able to change the content of the reference.
15. Acknowledgements
The authors would like to thank J. Rosenberg for providing the
'template' for this draft, Aki Niemi for giving good assistance, and
Krisztian Kiss and Jose Costa-Requena for reviewing the draft.
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-00 (work in progress), May 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)",
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
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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-00.txt (work
in progress), September 2003.
[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
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