Guidelines for Implementing the Dialog

Event Package in User Agents

Dale R. Worley

dworley@pingtel.com

Introduction to the dialog event package

Defined in draft-ietf-sipping-dialog-package.

Most components are optional, due to privacy concerns.

In order to be useful for end-point call control (e.g., call pick-up), the dialog package NOTIFY messages needs to contain certain of the optional items.

In order to be useful for call monitoring (e.g., attendant consoles), the to/from party information needs to be populated carefully.

Requires secruity as to who may SUBSCRIBE.

At SIPit 17, we tested 5 implementaitons; all had issues regarding these uses: Some were unusable for end-point call control. All were deficient for call monitoring.

Needed data items in the dialog event pacakge

Dialog identifiers and status: Call-ID, To-tag, From-tag, direction, state (early/established), duration

Parties: local/remote identity/target URIs

“Identity” should logically identify the user (AOR)

P-Asserted-Identity, etc.

To/From header (possibly as rewritten)

AOR associated with Requirest-URI of request

“Target” should be Contact URI (see RFC 3261)

GRUU, if available

Need to accept SUBSCRIBEs directed to:

contact URIs

UA address alone

INVITE sip:222@example.com SIP/2.0

Via: SIP/2.0/UDP pc33.example.com;branch=z9hG4bK776asdhds

Max-Forwards: 70

To: Bob <sip:222@example.com>

From: Alice <sip:111@example.com>;tag=1928301774

Call-ID: a84b4c76e66710@example.com

CSeq: 314159 INVITE

Contact: <sip:111@10.15.20.30>

SIP/2.0 200 OK

Via: SIP/2.0/UDP pc33.example.com;branch=z9hG4bK776asdhds

To: Bob <sip:222@example.com>;tag=dleicks

From: Alice <sip:111@example.com>;tag=1928301774

Call-ID: a84b4c76e66710@pc33.atlanta.com

CSeq: 314159 INVITE

Contact: <sip:222@example.com;opaque="xyzzy">

<dialog-info version="1" state="full">

<dialog id="123456" call-id="a84b4c76e66710@example.com"

local-tag="1928301774" remote-tag="dleicks"

direction="initiator">

<state>confirmed</state>

<duration>274</duration>

<local>

<identity display="Alice">sip:111@example.com</identity>

<target uri="sip:111@10.15.20.30"/>

</local>

<remote>

<identity display="Bob">sip:222@example.org</identity>

<target uri="sip:222@example.com;opaque="xyzzy""/>

</remote>

</dialog>

</dialog-info>

Example

Report

I have been compiling observations, requirements, and desiderata in draft-worley-sipping-dialog, “Guidelines for Implementing the Dialog Event Package in User Agents”.

In process as an I-D; currently available at http://scm.sipfoundry.org/rep/ietf-drafts/worley/draft-worley-sipping-dialog-00.txt

The current version is a rough draft, version 00.

Currently, there are 9 guidelines.

Implementors are invited to review it and contact me at dworley@pingtel.com.

2005-11-09T20:46:41