Version 2 of CPIM Subscription Data Format
[email protected] (John D. Ramsdell)
| Newsgroups | gmane.ietf.impp |
|---|---|
| Message-ID | <[email protected]> |
I IETF'ified the SDF document and modified it to use RFC2119 and
RFC2778 language.
John
----------------------------------------------------
Network Working Group John D. Ramsdell
INTERNET DRAFT The MITRE Corporation
Document Expires: ? May 2002
CPIM Subscription Data Format (DRAFT)
<draft-ramsdell-cpim-sdf-xx.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
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Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This memo specifies the CPIM Subscription Data Format (SDF) as a common
subscription data format for CPIM-compliant IM/Presence protocols.
Table of Contents
1. Introduction ...................................................... 2
1.1 Terminology and Conventions ...................................... 2
2. The SUBSCRIBE Operation ........................................... 2
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3. The 'application/cpim-subscription' Content Type .................. 3
4. Wrapping 'application/cpim-subscription' Data with 'message/CPIM' . 3
5. Examples .......................................................... 3
6. Acknowledgments ................................................... 4
7. References ........................................................ 4
8. Author's Address .................................................. 5
9. Full Copyright Statement .......................................... 5
1. Introduction
The Common Profile for Instant Messaging (CPIM) specifications define a
set of common operations and various formats to achieve interoperability
between different Instant Messaging and Presence protocols that meet RFC
2779 [RFC2779]. The CPIM core specification [CPIM] defines a set of
common operations and their parameters to be supported by interworking
Presence and IM protocols in order to allow straightforward gatewaying
between them. The CPIM Message Format [CPIM-MSG] defines a common
format for instant messages, which enables secure end-to-end IM exchange
through the gateways. The CPIM Presence Information Data Format [CPIM-
PIDF] defines a common presence data format for CPIM-compliant presence.
This memo further defines the CPIM Subscription Data Format (SDF) as a
common subscription data format for CPIM-compliant presence protocols.
The significance of the common subscription format primarily resides in
the fact that it provides a PRESENCE SERVICE means of identifying and
authenticating the SUBSCRIBER that is requesting PRESENCE SERVICE using
digital signatures. The use of both digital signatures and the
Subscription Data Format provides a protocol with a strong mechanism to
meet the requirement for authentication stated in [RFC2779, Section
5.1.12]. Without such a common subscription data format, the signed
content of a subscription request that traverses a gateway would not be
able to be validated.
1.1 Terminology and Conventions
This memo makes use of the vocabulary defined in the IMPP Model document
[RFC2778]. Terms such as CLOSED, INSTANT MESSAGE, OPEN, PRESENCE
SERVICE, PRESENTITY, WATCHER, and WATCHER USER AGENT in the memo 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 [RFC2119].
2. The SUBSCRIBE Operation
The SUBSCRIBE operation is used to request that a service deliver
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PRESENCE INFORMATION as specified in [CPIM]. As a side effect of a
successful SUBSCRIBE request, a PRESENCE SERVICE MUST initiate a NOTIFY
request that delivers the current PRESENCE INFORMATION contained by the
PRESENTITY targeted by the SUBSCRIBE request.
If, and only if the SUBSCRIBE request specifies a non-zero subscription
duration, a successful response MUST include the duration of the
SUBSCRIPTION granted by the service, and an identifier used to extend or
cancel the SUBSCRIPTION. As long as the SUBSCRIPTION has not lapsed,
when the PRESENCE INFORMATION changes, the PRESENCE SERVICE MUST
initiate a NOTIFY request that delivers the new PRESENCE INFORMATION to
the SUBSCRIBER.
A SUBSCRIPTION can be canceled with a SUBSCRIBE request that specifies
the SUBSCRIPTION's identifier and a duration of zero seconds. A
SUBSCRIBER cannot hold more than one SUBSCRIPTION. A PRESENCE SERVICE
MUST cancel a SUBSCRIPTION from a SUBSCRIBER if that SUBSCRIBER issues a
SUBSCRIBE request with a non-zero duration that does not contain the
original SUBSCRIPTION's identifier.
PRESENCE INFORMATION can always be fetched by issuing a SUBSCRIBE
request with a zero duration and no subscription identifier.
3. The 'application/cpim-subscription' Content Type
This memo defines a new content type, "application/cpim-subscription",
to encode subscription request specific data. The content is the
duration in seconds of the requested subscription, followed by an
optional subscription identifier. The syntax of the content follows
using [ABNF].
subscription-content = 1*DIGIT [ SP 1*DIGIT ] [ CR ] [ LF ]
A number contained in subscription-content MUST never exceed 2147483647.
4. Wrapping 'application/cpim-subscription' Data with 'message/CPIM'
CPIM message format MUST be used to carry a signable subscription
request. To do so, the CPIM message MUST contain content of type
"application/cpim-subscription". Any mechanism used to sign an instant
message in message/CPIM format may be used to sign a subscription
request in message/CPIM format. The CPIM message format MAY be used to
carry an unsigned subscription request.
5. Examples
A request for a SUBSCRIPTION that lasts an hour might look like:
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Content-type: message/CPIM
To: <pres:[email protected]>
From: <pres:[email protected]>
DataTime: 2002-04-04T13:40:00-08:00
Content-type: application/cpim-subscribe
3600
If the identifier returned with the response to above subscription
request is 99, the SUBSCRIPTION can be extend for thirty minutes with:
Content-type: message/CPIM
To: <pres:[email protected]>
From: <pres:[email protected]>
DataTime: 2002-04-04T14:20:00-08:00
Content-type: application/cpim-subscribe
1800 99
Even while SUBSCRIPTION 99 is being held, presence information can be
fetched with:
Content-type: message/CPIM
To: <pres:[email protected]>
From: <pres:[email protected]>
DataTime: 2002-04-04T14:10:00-08:00
Content-type: application/cpim-subscribe
0
6. Acknowledgments
Some introductory text was taken from [CPIM-PIDF].
7. References
[CPIM-MSGFMT]
D. Atkins and G. Klyne, "Common Presence and Instant Messaging
Message Format", draft-ietf-impp-cpim-msgfmt-06.txt, Work in
Progress.
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[RFC2119]
S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, BCP 14, March 1997.
[ABNF]
D. Crocker, and P. Overell, "Augmented BNF for Syntax Specifications:
ABNF", RFC 2234, November 1997. </sd:reference>
[CPIM]
D. Crocker et al., "A Common Profile for Instant Messaging (CPIM)",
draft-ietf-impp-cpim-02.txt, Work in Progress.
[RFC2779]
M. Day, S. Aggarwal, G. Mohr, and J. Vincent, "Instant Messaging /
Presence Protocol Requirements", RFC 2779, February 2000.
[RFC2778]
M. Day, J. Rosenberg, H. Sugano, "A Model for Presence and Instant
Messaging", RFC 2778, February 2000.
[CPIM-PIDF]
H. Sugano, S. Fujimoto, G. Klyne, A. Bateman, and W. Carr, "CPIM
Presence Information Data Format", draft-ietf-impp-cpim-pidf-03.txt,
Work in Progress.
8. Author's Address
John D. Ramsdell
Mail Stop K329
202 Burlington Road
Bedford, MA 01730-1420
[email protected]
9. Full Copyright Statement
Copyright (C) The Internet Society (2002). All Rights Reserved.
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except as needed for the purpose of developing Internet standards in
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Standards process must be followed, or as required to translate it into
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languages other than English.
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This document and the information contained herein is provided on an "AS
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