SIPPING Working Group G. Camarillo
Internet-Draft Ericsson
Expires: May 22, 2004 A. Roach
dynamicsoft
November 22, 2003
Providing a Session Initiation Protocol (SIP) Application Server with
a List of URIs
draft-camarillo-uri-list-00.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document describes how a user agent can provide an application
server with a list of URIs. The way the application server uses the
URIs in the list is service specific.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The SIP and SIPS URI List Parameter . . . . . . . . . . . . . 3
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1 Ad-Hoc Conference . . . . . . . . . . . . . . . . . . . . . . 4
4.2 Presence List . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
Normative References . . . . . . . . . . . . . . . . . . . . . 7
Informational References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . 9
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1. Introduction
The need for exploders in SIP is described in [5]. Mechanisms to
invoke exploders in SIP need to meet the requirements listed there.
UAs need to have a means to provide application servers with a set of
URIs for certain services. A UA creating a conference needs to
provide the conference server with the participants. A UA requesting
presence information from a set of users needs to provide the
resource list server with the URIs of the users that belong to the
list.
These lists are typically configured using out-of-band methods. For
instance, a UA can use XCAP [4] to create a list of URIs and to
associate this list with a SIP URI. It can, then, send a SIP request
(an INVITE or a SUBSCRIBE in our previous examples) to that SIP URI.
Nevertheless, there is a need to create lists of URIs in an ad-hoc
way and send them directly in a SIP message. We use Content-ID URLs
[2] and XCAP resource lists (draft-ietf-simple-xcap-list-usage)
encoded in MIME bodies [3] for that purpose. We also define a SIP and
a SIPS header field parameter called "list".
2. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as
described in BCP 14, RFC 2119 [1] and indicate requirement levels for
compliant implementations.
3. The SIP and SIPS URI List Parameter
We define the "list" parameter for SIP and SIPS URIs. It MUST contain
a URI that points to an XCAP resource list. Its ABNF is:
list-param = "list=" absoluteURI
The following is an example of a SIP URI with a list parameter
pointing to a body part using a Content-ID URL:
sip:group@example.com;list=cid:cn35t8jf02@example.com
The following is an example of a SIP URI with a list parameter
pointing to an external URI:
sip:group@example.com;list=http://xcap.example.com/lists/mylist.xml
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4. Examples
This section shows how to use the list parameter to create an ad-hoc
conference and to subscribe to the presence information to a set of
users.
4.1 Ad-Hoc Conference
Carol creates an ad-hoc conference by sending the INVITE request
shown in Figure 1. The list parameter in the Request-URI points to a
MIME body that carries the list of participants.
INVITE sip:ad-hoc@example.com;list=cid:cn35t8jf02@example.com SIP/2.0
Via: SIP/2.0/TCP client.chicago.example.com
;branch=z9hG4bKhjhs8ass83
Max-Forwards: 70
To: "Ad-Hoc Conferences" <sip:ad-hoc@example.com>
From: Carol <sip:carol@chicago.example.com>;tag=32331
Call-ID: d432fa84b4c76e66710
CSeq: 1 INVITE
Contact: <sip:carol@client.chicago.example.com>
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
SUBSCRIBE, NOTIFY
Allow-Events: dialog
Accept: application/sdp, message/sipfrag,
application/resource-lists+xml
Conten-Type: multipart/mixed;boundary="boundary1"
Content-Length: xxx
--boundary1
Content-Type: application/sdp
Content-Length: xxx
v=0
o=carol 2890844526 2890842807 IN IP4 chicago.example.com
s=Example Subject
c=IN IP4 192.0.0.1
t=0 0
m=audio 20000 RTP/AVP 0
m=video 20002 RTP/AVP 31
--boundary1
Content-Type: application/resource-lists+xml
Content-Length: xxx
Content-ID: <cn35t8jf02@example.com>
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<?xml version="1.0" encoding="UTF-8"?>
<resource-lists xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<list name="ad-hoc-1">
<entry name="1" uri="sip:bill@example.com" />
<entry name="2" uri="sip:joe@example.com" />
<entry name="3" uri="sip:ted@example.com" />
<entry name="4" uri="sip:bob@example.com" />
</list>
</resource-lists>
--boundary1--
Figure 1: INVITE request
SIP/2.0 200 OK
Via: SIP/2.0/TCP client.chicago.example.com
;branch=z9hG4bKhjhs8ass83;received=192.0.2.4
To: "Ad-Hoc Conferences" <sip:ad-hoc@example.com>;tag=733413
From: Carol <sip:carol@chicago.example.com>;tag=32331
Call-ID: d432fa84b4c76e66710
CSeq: 1 INVITE
Contact: <sip:3402934234@example.com>;isfocus
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
SUBSCRIBE, NOTIFY
Allow-Events: dialog, conference
Accept: application/sdp, application/conference-info+xml,
message/sipfrag
Supported: replaces, join
Content-Type: application/sdp
Content-Length: 274
v=0
o=focus431 2890844526 2890842807 IN IP4 ms5.conf.example.com
s=Example Subject
i=Example Conference Hosted by Example.com
u=http://conf.example.com/3402934234
e=3402934234@conf-help.example.com
p=+1-888-555-1212
c=IN IP4 ms5.conf.example.com
t=0 0
m=audio 49170 RTP/AVP 0
m=video 51372 RTP/AVP 31
Figure 2: 200 (OK) response
The conference server responds with a 200 (OK) that carries the URI
for the conference in its Contact header field. If the UA wants to
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obtain information about the status of the conference, for instance,
it will SUBSCRIBE to the conference package using this URI.
4.2 Presence List
Carol subscribes to the presence information of four of her friends
using the list parameter.
SUBSCRIBE sip:ad-hoc@example.com;list=cid:cn35t8jf02@example.com SIP/2.0
Via: SIP/2.0/TCP client.chicago.example.com
;branch=z9hG4bKhjhs8ass83
Max-Forwards: 70
To: "Ad-Hoc Presence List" <sip:ad-hoc@example.com>
From: Carol <sip:carol@chicago.example.com>;tag=32331
Call-ID: d432fa84b4c76e66710
CSeq: 1 INVITE
Contact: <sip:carol@client.chicago.example.com>
Require: eventlist
Event: presence
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
SUBSCRIBE, NOTIFY
Allow-Events: presence
Accept: application/sdp, message/sipfrag,
application/resource-lists+xml, application/rlmi+xml
Content-Type: application/resource-lists+xml
Content-Length: xxx
Content-ID: <cn35t8jf02@example.com>
<?xml version="1.0" encoding="UTF-8"?>
<resource-lists xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<list name="ad-hoc-1">
<entry name="1" uri="sip:bill@example.com" />
<entry name="2" uri="sip:joe@example.com" />
<entry name="3" uri="sip:ted@example.com" />
<entry name="4" uri="sip:bob@example.com" />
</list>
</resource-lists>
--boundary1--
Figure 3: SUBSCRIBE request
OPEN ISSUE: here Content-ID appears as a SIP header field. Either we
sub-encode the body as a MIME part or we define that header field in
SIP
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5. Security Considerations
TBD.
6. IANA Considerations
TBD: we need to register the SIP/SIPS URI parameter "list".
Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Levinson, E., "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, August 1998.
[3] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies",
RFC 2045, November 1996.
Informational References
[4] Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)",
draft-ietf-simple-xcap-01 (work in progress), October 2003.
[5] Camarillo, G., "Requirements for Session Initiation Protocol
(SIP) Exploder Invocation", draft-camarillo-sipping-exploders-00
(work in progress), September 2003.
Authors' Addresses
Gonzalo Camarillo
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
EMail: Gonzalo.Camarillo@ericsson.com
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Adam Roach
dynamicsoft
5100 Tennyson Pkwy
Suite 1200
Plano, TX 75024
US
EMail: adam@dynamicsoft.com
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