Subject: [Sipping] A new draft on P2P SIP

From: Philip Matthews <[email-masked]>
Date: Mon, 14 Feb 2005 17:24:25 -0500

My co-worker, Behrouz Poustchi, and I have submitted a brief draft 
contributing to the discussion around P2P SIP. In it, we present some
features that we would like to see considered in any P2P SIP standard
(or whatever it is going to be), based on our experience in this area.

We are new to the SIPPING working group, but we hope that our draft
is a positive contribution to the subject, and would be happy to 
participate in any work that is done in this area.

The draft is available at:

http://www.ietf.org/internet-drafts/draft-matthews-sipping-p2p-industrial-strength-00.txt

Comments on the draft are very welcome.

- Philip Matthews

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From: Arjun Roychowdhury <[email-masked]>
Date: Tue, 15 Feb 2005 11:17:17 -0500

Philip:

some quick comments:

*) Is this document a requirements document or an archirecture
document ? It seems to have a little of both. Also, before we have a
requirements specification on what a P2P network must do, one needs to
have a common understanding/agreement on what really is a SIP P2P
network and what goals it acheives. Your draft seems to concentrate
only on telephony features. I am not sure if this is the only
motivation. Either way, I would like to see more discussion on the
scope

*) I would suggest you not use the term that this draft addresses
"Industrial-Strength" P2P while others may not. I believe one of the
goals of the IETF is to specify real-life/stable solutions/protocols
and I am sure this would also be the goal for any alternate drafts. If
you believe that your I-D addresses a different network from others,
do state it as so (I believe that is your intent)

*) I don't believe the abstract of the draft really summarizes what is
the scope of the document. For example, the draft mainly focuses on
the need to provide the same functionality a PBX has without really
having one. However, it does not talk about challenges in user/node
discovery, fault management, cross network interop issues, Firewall
traversal   and such that a p2p network may address. If these are not
addressed, then the scope of just replacing a PBX will intelligent
phones in a defined/closed network becomes a much simpler issue.

*) Section 3 seems to reccomend a functional architecture at a
simple/20,000 feet view. I am not sure if this should be a part of a
document when the need/scope/requirements are yet to be fleshed out.
Also, since Section 3 is at such a high level, it is difficult to be
able to discuss/argue on the need/functionality of this 3 level
architecture.

regds
arjun

-- 
Arjun Roychowdhury

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From: Philip Matthews <[email-masked]>
Date: Wed, 16 Feb 2005 13:25:30 -0500

Hi Arjun:

Thanks for your comments.

I agree that our draft is a mixture of requirements
and high-level architecture. Initially, our goal was
to write a draft that called attention to a class of
applications in which P2P SIP has equal functionality
to existing telephony networks. Our impression is that
most of the discussion (in drafts and on the mailing list)
has revolved around what we called "ad-hoc" networks
in the draft.We used the term "industrial-strength" to
differentiate us. It was *not* our intention to disparage
anyone else's work. However, as you point out, its use
can be misconstrued, and it was perhaps not the best choice.

In the interest of keeping our draft focused and short,
we only mentioned features that had not been discussed
by others. We then decided to add the section on high-level
architecture because, in our experience, keeping the
P2P and SIP layers separate is very beneficial.

We totally agree with you that there needs to be more
discussion of the requirements for P2P SIP. It is our hope
to have a first cut of a requirements document out in the
next few weeks to help this process along.

You are right that our draft only concentrates on telephony
features. It is the application that we understand. However,
it seems like you have other applications of P2P SIP in mind.
I can only think of instant messaging.
What do you envision?

- Philip

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From: Arjun Roychowdhury <[email-masked]>
Date: Fri, 18 Feb 2005 10:44:39 -0500

Philip, sorry for the delayed response.
I guess I am not very clear on the intent of the draft. Did you take a
look at Xiaotao and Henning's recently released draft on LESS ? Is
this what you were getting at ?

regds
arjun

-- 
Arjun Roychowdhury

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From: Philip Matthews <[email-masked]>
Date: Tue, 22 Feb 2005 15:27:28 -0500

Hi Arjun:

As I understand it, Xiatao and Henning are proposing a language
to describe various call treatment options.

What we are saying, among other things, is that the network
needs to support these options.

For example, consider user B on a P2P network with a wireless
phone and voicemail. If user B is out of wireless range,
then how does caller A leave a voicemail message for user B?
In a centralized (non-P2P) network, this is easy -- leave it
on some centralized server. But in a P2P network, where do
you leave the message, and how does user B retrieve the message
once her phone is back in range?

These are the types of problems we talk about in the draft.

- Philip