[p2p-hackers] Is P2P SIP Poised to Out-Hype Skype? (Voxilla)

Mon Aug 22 02:27:30 UTC 2005

Well, you say that VoIP is not illegal. A lot of thing used not to be, and
were criminalized by statute; some, like encryption for the masses,
managed to escape only because it was too late to enforce prohibition. And
in some countries, VoIP _is_, or may become, illegal, either for political
reasons (especially secure VoIP: ever heard of CALEA?) or just to protect
inefficient government monopolies (see e.g.
http://www.techweb.com/wire/networking/60403862 ). In the end,
unenforceability is Liberty's best friend.

And then, there is the issue of ease of use: centralized solutions need a
multiplicity of providers, because nobody wants to see a FWD or Sipphone
close down or go commercial and start charging annual fees. But multiple
providers means multiple accounts, and, often, balkanized user bases
unable to cross provider borders (as each provider likes to protect its
flock from other shepherds -- or, with a probably more fitting metaphor,
its harem from other sultans ;-) ). This results in complications in the
setup and smallish user communities. The proof of the pudding is in the
making: Skype, despite being far from ideal in terms of openness,
certifiable security and interoperability, has 50 million users. How many
do FWD or Sipphone have?

Actually, a system of centralized but open and interoperable telephone
directories (based on the DNS) already exists, and it's called ENUM:
essentially it allows to convert an E.164 telephone number into a (SIP,
IAX, H.323...) URI. There is at least one independent and free registrar
offering ENUM service to the public: www.e164.org . Due to the distributed
caching operated by the DNS, the load on the actual registrar is quite
small, further reducing its operating costs (it's like running a
conventional authoritative DNS server). However, the DNS is by itself
vulnerable to attacks: in Mainland China, for example, all the DNS queries
to foreign servers are transparently rerouted to internal servers that
return answers with random RR's if the domain name is blacklisted (I've
recently had to abandon em.no-ip.com because all the subdomains of
no-ip.com were blacklisted, and so are dyndns.org's). A really robust
directory service must be fully distributed (e.g., DHT based) and
port-flexible, rather than relying upon well-known ports. Grafting these
characteristics over a DNS-based mechanism is also possible, although not
very convenient for non-technical users: see e.g. my namecache daemon
(http://kadc.sourceforge.net/apps.html#namecache ), which however is
presently limited to A records, and can't yet handle the NAPTR records
used by ENUM.

Cheers --

Enzo

P.S.

----- Original Message ----- 
From: "David Barrett" <dbarrett at quinthar.com>
To: "Peer-to-peer development." <p2p-hackers at zgp.org>
Sent: Monday, August 22, 2005 9:13 AM
Subject: Re: [p2p-hackers] Is P2P SIP Poised to Out-Hype Skype? (Voxilla)

> I wrote some comments on Eric's blog (sipthat.com) detailing why I
disagree:
>
> http://sipthat.com/archives/000351.html
>
> Aswath has another relevant article:
>
> http://www.mocaedu.com/mt/archives/000168.html
>
> Basically, I think P2P is useful to reduce legal vulnerability, obtain
> high security, minimize bottlenecks, and distribute computation.  None
> of these applies to SIP proxies, which are essentially directory-based
> "rendezvous" services.
>
> That said, all of these certainly apply to the actual media components
> (audio, video, etc).  But these are generally RTP.  The SIP part is very
> low cost, low CPU, low bandwidth, and benefits from centralization.
>
> My original comments to Eric's article follow:
>
> -----Original Message-----
> From: David Barrett [mailto:dbarrett at quinthar.com]
> Sent: Tuesday, August 02, 2005 3:11 AM
> To: erik at sipthat.com
> Subject: Re: P2P VoIP using SIP and Open Standards
>
> Hi, sorry for the late reply to your July 25th posting about P2P SIP,
but
> you posed the question:
>
>
> >> Everyone is looking for a new solution for P2P VoIP, I think P2P
> >> SIP is the answer, do you?
>
>
> My answer is no, I don't believe P2P SIP is the key to P2P VoIP. More
> specifically, I don't think an IETF standard for decentralized SIP
proxies
> will gain traction because it solves problems that nobody has, while
> complicating the problems that we do.
>
> Now, I recognize VoIP will grow, and the actual media components will
> migrate to P2P. But I do not believe the SIP proxy component of the
global
> architecture gains anything by being decentralized in this way.
>
> My reasoning is based on the observation that P2P is primarily useful in
two
> situations:
>
> a) When a centralized solution is too costly
> b) When a centralized solution is legally vulnerable
>
> Consider the case of Napster. A kid in a college dorm room was able to
host
> a global rendezvous service (akin to a SIP proxy) for millions of
> simultaneous users, for free. Obviously, he didn't suffer from (a).
> But (b) was what took him down, and thus gave rise to Gnutella (et al).
>
> But had (b) not occurred (ie, had the courts ruled in favor of Napster),
I
> offer that Gnutella simply would not exist because it offers precisely
zero
> incremental value. It is slower, less reliable, and less comprehensive
than
> Napster could have been. Had Napster been allowed to grow, it could have
> offered better services, evolved faster, and been superior in every
> measurable way.
>
> SIP proxies are today like Napster was then. But VoIP isn't illegal, and
> thus a SIP proxy is not a legal vulnerability. Thus I see no reason to
> believe that a decentralized alternative to a SIP proxy would warrant
the
> resulting complexity cost inherent in any "pure"-P2P solution.
>
> All that said, I do believe that P2P is the future of VoIP, and
near-free
> services will be the business model. I merely think that the SIP proxy
part
> of the equation is best left centralized.
>
> -david
> Posted by: David Barrett at August 6, 2005 01:01 AM
>
> So again, I'm still not sold on the benefits of P2P SIP. I think it's
> cool, don't get me wrong. And the idea of setting up an instant P2P
> network in the middle of a desert or in a disaster area is appealing,
> certainly. But you have to admit those are rather extreme circumstances.
> For the remaining 99.999% of actual real world users, this is not the
case.
>
> Furthermore, I agree that the servers at Free World Dialup and other
> free SIP services cost money. But not much, else they wouldn't be free.
> For under $100/mo you can get a dedicated server right on the backbone.
> The cost of deploying and maintaining hardware is virtually negligible
> these days.
>
> The real costs come in managing the network, and this is where
> centralized services come in handy.
>
> So P2P SIP is cool, certainly. And it might be handy the extreme
> situations you offer. But by the time the intrinsic decentralized
> problems have been hammered out, a centralized alternative will already
> dominate the landscape. And when it comes to competition, the
> decentralized solution offers no significant real world advantage (cost,
> reliability, performance) to anyone (user, administrator), while
> offering significant drawbacks in terms of complexity and the overall
> uncontrolled nature of P2P.
>
> Would you disagree? I mean, except for disaster areas and deserts, and
> except for saving $100/mo for a million users, what's the benefit?
>
> Furthermore, do you acknowledge the disadvantages in terms of
> reliability and performance (ie, global distributed search versus
> database lookup) of a P2P solution? How would you argue the benefits
> outweigh the detriments?
>
> -david
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