Subject: [Sipping] new proposed BoF and mailing list on feature interoperability

From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 19 Jan 2007 16:03:17 -0500

Please do not reply to this mail.

SIP has come a long way in terms of interoperability over the years. 
However, there are several places where we still have a poor track 
record of interoperability. One of these is in the area of more advanced 
types of features. These include many of the features traditionally 
found on enterprise PBXs, such as park/pickup, shared line extension, 
and so on. There has been sporadic work on this topic, with many drafts, 
but no real solution yet.

There is a real need to get these interoperability problems solved. This 
need is coming from the IP PBX/Centrex side and from the consumer side, 
from groups like TISPAN that want some of these features to work.

The interop problems stem from several root cause issues. One is too 
much variety in the way these features can be implemented. This is good 
from a flexibility point of view, but it causes interop problems when 
both endpoints do things differently and won't work together as a 
consequence. Another problem is lack of sufficient functionality from 
the specs, in which cases people turn to proprietary techniques. Combine 
this with the standard "dont want to implement the right thing because 
its too hard" and general bug problems, and its a mess.

To fix this, I think it makes sense to start a working group thats 
formally tasked with the problem. The idea is to take on individual 
features, one at a time, figure out the real issues causing interop 
problems, and address them by either writing some requirements for sip 
enhancements, or developing some BCPs or informational documents 
specifying minimum interop requirements. Its also important to do this 
without trying to formally define what the feature is; we want to allow 
variation as much as possible while preserving interop.

I've been with Cullen, Shida Schubert and a number of others on getting 
a BoF going in Prague on this. We've got a mailing list that is now set 
up, and a proposed charter, all of which can be found here:

http://sip101.net/index.html

Please join the list and participate in the discussions. The more of it 
we can have prior to Prague, the better the chances we can arrive there 
with a charter and deliverables that are on target.

Thanks,
Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com

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