Subject: [p2p-sip] Some comments on Use-cases document

From: huang-ming.pan at comcast.net (Peter Pan)
Date: Mon, 27 Mar 2006 09:23:45 -0800

Not only on P2P species, if the comparison between Jabber and SIP in
attached paper is not too exaggerating, especially regarding "Bandwidth
Requirements and Scalability Implications", SIP protocol may need revamps
before acting as a P2P "wrapper" protocol.

http://www.jabber.com/index.cgi?CONTENT_ID=55&VMX_TRACKED=YES

Just thought the place should have more open minds for both positive
suggestions and negative challenges, even bitter critiques; otherwise it is
just another piece of tofu under construction like the volunerable Windows.

peter
----- Original Message -----
From: Henry Sinnreich
To: 'Mike Robinson' ; 'Karst Bjorgson' ; 'Kyara Yamamoto' ; 'Peter Pan'
Cc: p2p-sip at cs.columbia.edu
Sent: Monday, March 27, 2006 8:17 AM
Subject: RE: [p2p-sip] Some comments on Use-cases document

Mike Robinson writes:

>How many research ! or analytical papers have been published in this area?
I have found by Googling a reference listing 4,800 papers on P2P. Hopefully,
this enough to get us started. J
Henry

From: p2p-sip-bounces at cs.columbia.edu
[mailto:p2p-sip-bounces at cs.columbia.edu] On Behalf Of Mike Robinson
Sent: Sunday, March 26, 2006 2:36 PM
To: Karst Bjorgson; Kyara Yamamoto; Peter Pan
Cc: p2p-sip at cs.columbia.edu
Subject: Re: [p2p-sip] Some comments on Use-cases document

Hello Karst:

Thanks explaining your "consipracy" rationale..

After following the  discussion  in BOF and  in ad-hoc meetingin IETF, it
appears that certain people are more interested in pushing their personal
agendas of p2p sip than caring for technical merits of this group. Now that
I understand your point of view, and details a bit better, and it appears to
me that p2p sip idea as being proposed  seems to have a real "conspiracy"
behind it.

Why are are we trying to standadize some thing in hurry that is so
ill-defined and is not yet ready for standardization?  How many research !
or analytical papers have been published in this area? Perhaps none! Several
people, I talked to seem to favour sip over p2p rather than what is being
proposed by the current crop of people that are pushing their solution with
limited implementation experience. May it is some IPR thingy or something I
don't understand well the politics of it. When a company and University work
together, I usually become suspicious of their motivation.

Karst Bjorgson <karstbj at yahoo.com> wrote:
> Could you please elaborate on why do you say "
> Linking P2P SIP
> to a particular DHT is specific conspiracy does not
> appear very wise.".

Most of the DHT technologies are still at the research
level. We can expect significant progress in security,
handling of locality, amount of management overhead,
etc. Ths, we may well expect that a DHT implementation
that looks attractive now will look terrible in say,
five years. This calls for a level of indirection.

Hmm....
Looks like we haven't yet reached a stage where we can really
talk of  a particular DHT being standardized in a IETF protocol.

I used the word "conspiracy" to denote the tight
coupling between notes expected in many DHT
technologies. The INSERT primitive, in most systems,
finds the node "closest" to the inserted index, and
asks that node to publish the value. In practice, this
requires a lot of trust: trust that a third party will
publish your data, just because the hash code of their
node-id is closest to the hash code of your name. That
kind of trust is easier to obtain! in small groups than
in very large systems. Thus, even if we picked a
single DHT technology, we would still want a level of
indirection to indicate which particular DHT group
should be used.

I see your point - it appears that technology needs more research
before it can be standardized. I believe there is an IRTF sub-group
researching into DHT implementations and other P2P area.  Formation
of this group should perhaps wait till some more input from IRTF is
available in this direction. Moreover, I didn't see a very compelling use
case that says the p2psip is needed right away. It does not do any thing
that cannot be done with sip at least in the enterprise network
that I am familiar with.

I hope area director is reading this list.

> What is wrong with Chord that is being suggested?

I would rather b! e modest here -- Chord is a nice piece
of work, and I enjoyed reading their papers. I am
concerned mostly with two aspects: the possibility for
bad nodes to insert themselves at strategic point in
the "routing tables"; and the amount of overhead
required for table maintenance. That does not mean we
cannot use Chord, but I believe it would be a mistake
to not plan for technical evolution.

Thanks for putting this information in a clear perspective.
I do agree with your assessment.

--mike
VOIP and SIP Trainer and Consultant

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