Subject: [p2p-sip] P2P SIP Motivation

From: lists at bulukucing.org (Benny Prijono)
Date: Mon Aug 8 10:29:05 2005

Dear all,

just as I'm eager to follow the development of P2P standard using SIP, I 
have yet still remain unconvinced about the real need to have a P2P SIP. 
The draft (draft-bryan-sipping-p2p-01.html) promises to explain the 
motivation, but the sample usage scenarios described in the introduction 
doesn't seem to convince me.

So I need to ask this very naive question (sorry).

Why do we need P2P. I thought that the ideal communication model 
endorsed by IETF is where people subscribe (register) to different 
ITSP/domains (just like ISP) and then they would be able to 
call/chat/conference people on different domains (just like email), 
ideally for free. If I were visiting my parents in East Java, I would 
then just use local ISP's proxy as outbound proxy or whatever, and still 
register to my main ITSP so that others can call me.

I know that *probably* current services offerred by ITSPs at the moment 
prohibit people from calling others/receiving calls from outside the 
domain, thus creating "walled gardens" between different ITSPs. But 
wouldn't P2P create another walled garden, where you still wouldn't be 
able to call your friends@ITSP? Of course you can call your friend@ITSP 
if the ITSP allows its subscribers to receive calls from outside the 
domain, but when this happens, why would we still need P2P then?

Please someone shed a light.

thanks,
benny

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From: mah at inode.at (Michael Haberler)
Date: Mon Aug 8 18:25:48 2005

At 22:30 08.08.2005, Benny Prijono wrote:

>Why do we need P2P. I thought that the ideal communication model endorsed 
>by IETF is where people subscribe (register) to different ITSP/domains 
>(just like ISP) and then they would be able to call/chat/conference people 
>on different domains (just like email), ideally for free. If I were 
>visiting my parents in East Java, I would then just use local ISP's proxy 
>as outbound proxy or whatever, and still register to my main ITSP so that 
>others can call me.
>
>able to call your friends@ITSP? Of course you can call your friend@ITSP if 
>the ITSP allows its subscribers to receive calls from outside the domain, 
>but when this happens, why would we still need P2P then?

I join the fool's league - that's something I had been asking myself - what 
is the problem being adressed, given that the cost of operating a SIP proxy 
and owning a domain is next to zero in the first place?

looking at skype:
what is P2P here is a *distributed media relay* (that clearly saves cost, 
might scale, great idea)
target discovery might be P2P, few savings here but who cares - DNS, 
databases actually do work (what problem is actually being fixed here by P2P ?)
authentication is centralized, no savings wrt SIP proxy
media gateways to/from PSTN centralized too, same as above

unsolved problems:
certified identity - orthogonal but potentially worse except if fallback to 
centralized authentication (well guess what skype does for billable services)
related to that: spam/spit - no change attributable to the core concept
SIP/SIMPLE efforts convergence on something 
implementable/interoperable/deployable - as above

potential upsides: getting around political problems with ITU, ICANN, 
CALEA, regulators etc, time to market  - most of which could be downsides 
in some respect too. My personal experience is that these problems are 
tractable.

I cant see the walled garden problem you are mentioning - this effort which 
is obviously geared towards a standard, interoperable and all.

I like the P2P concept and algorithms, sounds cute, all the rage these 
days, wrt to standards-based VoIP/IP communications adoption thats 
currently rearranging deckchairs on the Titanic for me.

But I might be overlooking something. Flame & enligthen me.

just as naive & lost in Vienna.

-Michael
MBA at times