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Optical/IP

P2P & VOIP: Coming Together?

Ever since KaZaA founder Niklas Zennstrom let it slip in a Boardwatch interview that he was planning to launch a company offering voice services using peer-to-peer (P2P) protocols, Light Reading and Boardwatch have been puzzling over what he meant.

As Zennstrom himself has clammed up, speculation is in order. And our best guess is that he might be onto something REALLY BIG. Think bigger than Google. Think of something equivalent to the Internet's Domain Name System (DNS) that would act as a distributed, dynamic, global telephone directory, linking users with whatever IP address their appliance happened to be using at the moment.

This addresses one of the big obstacles in the development of voice over IP (VOIP), and it might also unlock other breakthroughs. For instance, it could speed up the convergence of fixed and mobile telephony -- reckoned by Niel Ransom, CTO of Alcatel SA (NYSE: ALA; Paris: CGEP:PA), to be the next big thing in telecom (look for the coming Light Reading interview).

It would be fairly straightforward to use P2P protocols to create such a distributed, global telephone directory, according to Geoff Bennett, director of Light Reading University, who happens to be moderating a Light Reading Webinar titled "Controlling P2P: Who's Stealing Your Bandwidth?" today, at 2:00 p.m. New York time. (Click here to register for the free, live broadcast.)

With P2P, a user could search a directory using a special browser and then click on the name he or she wanted to call. The client software would send the request to the equivalent of a KaZaA supernode that would search a giant routing table listing users and their current IP addresses, and send back the result to the client so the VOIP call could be set up.

This is pretty much how file sharing works, and file sharing clearly scales to the millions of users that might take advantage of such a system. Zennstrom estimates that 100 million people already use P2P protocols, and the KaZaA browser software has been downloaded a staggering 250 million times -- an order of magnitude more than anything else on CNET's download site.

There are good reasons to believe that a P2P-based phone directory of this sort might work better than the VOIP solutions being cooked up by the Internet Engineering Task Force (IETF).

The IETF has various projects in this area, but they're all based on the fundamental philosophy that existing technology -- namely DNS -- should be adapted to deal with new requirements, rather than inventing something new.

But the new requirements in this case include more than just the IETF's Telephone Number Mapping (enum) project.

The IETF has also got to come up with a way of making DNS more dynamic, so that when a user moves from one IP address to another, he or she isn't cut off from the world while the changes propagate through the DNS hierarchy. When Boardwatch changed IP address earlier this year, a lot of readers were cut off for two or three days. Imagine the same thing happening every time someone shifted from a fixed to a mobile appliance!

Then there's the issue of reliability. Concerns are often expressed about the security of DNS -- in particular, its vulnerability to denial-of-service (DOS) attacks. A P2P approach promises to be much more reliable, because it's so distributed and because the protocol has been designed to allow for parts of the network going AWOL unexpectedly.

"Historically, the issue with proprietary solutions has been lack of scaleability, and how robust they are in large networks," Bennett notes. "But P2P apps like KaZaA have shown they can scale and have amazing resilience because they're so distributed. How do you make a DOS attack on something that big?

"The P2P solution will obviously be proprietary, and it's always quicker to get a proprietary solution to market than to wait for consensus in a standards group -- especially about something as institutionalized as DNS."

For more on IETF side of the story, check out the following columns by Geoff Huston, a member of the Internet Architecture Board, the IETF steering body: Light Reading is rather hoping that this speculation will encourage Zennstrom to spill the beans on what he's up to. Right now, we think we've only got half the story. The other half concerns SIP -- the Session Initiation Protocol -- seen by some as another catalyst for a VOIP explosion. In the Boardwatch interview Zennstrom slapped down the idea that his project had anything to do with SIP. Which leads us to ask: Why was he so adamant?

— Peter Heywood, Founding Editor, Light Reading

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echo2 12/4/2012 | 11:42:16 PM
re: P2P & VOIP: Coming Together? It is not part of the do-not-call registry.
boozoo 12/4/2012 | 11:42:15 PM
re: P2P & VOIP: Coming Together? I think the article hinted that the biggest problem is reconciling/changing the current telephone number with a "standard internet phone address"
This address can be anything, ranging from an IP address to an email address to a passportId or yahooId or AOLId or maybe something that has not been invented yet).

So far I have not seen a serious driving force towards creating such a "phone address" that would replace the E.164 address.
Of course, telcos don't have any interest in promoting the change, since they will lose the monopoly over the signalling of the voice calls.

But sooner or later, there's going to be a revolution in this segment as well.

Boozoo

dljvjbsl 12/4/2012 | 11:42:15 PM
re: P2P & VOIP: Coming Together?
The P2P protocols that are mooted about in this article may work but they cannot possibly work in the way described in the article.

What happens if the device that the user is currently at does not support VoIP?

What happens if the user does not want to be disturbed?

What happens if the user is available at multiple IP addresses?

The telephone network, SIP and even H.323 have answers for all of these questions and the many more that would arise with even a brief analysis. It would seem that either the article or the proposal will need to be greatly expanded
gbennett 12/4/2012 | 11:42:14 PM
re: P2P & VOIP: Coming Together? dljvjbsl wrote:

The P2P protocols that are mooted about in this article may work but they cannot possibly work in the way described in the article.


Actually we didn't really describe the operation of the protocols, as Mr.Z is remaining shtum on that point of detail :-)

If you want me to guess, the Kazaa-like protocol would take the place of the proposed enum lookup, while a new SIP-like protocol would handle the call setup.

As Peter says, Zennstrom is pushing back quite hard on SIP. One of the other posters for the original article raised the prospet of "audio pop up ads" whenever you dial a phone number :-)

If the new system used SIP, it'd be easier to hack together a client that could bypass the ads - a bit like Kazaa Lite does for pop ups (so I'm told :-)

Cheers,
Geoff
boozoo 12/4/2012 | 11:42:14 PM
re: P2P & VOIP: Coming Together? Just an observation:

The power of a E.164 address is that it contains routing information embedded in the address, in other words is self-suficient. You can send information to the address just by looking at it.
The disadvantage is that being geographically-bound, it's tough to find a scalable solution for E.164 address mobility.

An IP address or email address or whatever relies on the routing protocols or DNS for routing. The important consequence here is that state information needs to be stored somewhere (routing tables, Databases) about how to send information to this addess.
This is not minor issue, since it has scalability implications.

Boozoo
gbennett 12/4/2012 | 11:42:13 PM
re: P2P & VOIP: Coming Together? Hi boozoo,

Actually Geoff Huston's "Who are You" article gives a very nice explanation of these points. He keeps the discussion low key and doesn't get too bogged down in technical detail. It's an excellent intro for those of you who haven't considered the implications before.

For instance he raises the issue of "semantic overload" on IP addreses, attempting to act as a routing mechanism and a potential identifier.

Mobility's an equally challenging problem in the IP world, of course. We may think that IPv6 routing tables can be smaller than IPv4 because of more efficient prefix supernetting, but mobility blows a hole in that one (even if the lack of effective, geographical address assignment didn't).

Cheers,
Geoff
aswath 12/4/2012 | 11:42:09 PM
re: P2P & VOIP: Coming Together? gbennett wrote: If the new system used SIP, it'd be easier to hack together a client that could bypass the ads...

Whatever the scheme is why not we use the KaZaA browser to retrive the peer's IP address and then use the standard client like Netmeeting or Windows Messenger to establish the session?

Aswath
aswath 12/4/2012 | 11:42:07 PM
re: P2P & VOIP: Coming Together? I am missing the point of the observation "The power of a E.164 address is that it contains routing information embedded in the address, in other words is self-suficient."

Don't we lose the geographical significance of E.164 addresses with Toll-free number, Number portability and mobility? Don't SCP and HLR/VLR take on similar role as DNS as far as address translation function goes?

Aswath
dljvjbsl 12/4/2012 | 11:42:04 PM
re: P2P & VOIP: Coming Together?
If you want me to guess, the Kazaa-like protocol would take the place of the proposed enum lookup, while a new SIP-like protocol would handle the call setup.


This seems fine except that I really do not see the difference with SIP and it does not really jibe with the description in the article.

SIP is a 'one number' service. A user is contactable though a proxy that he registers in some directory or gives to his approved callers. The user registers his current preferred addresses for contact and can supply a a CPL script to filter callers.

SIP or ENUM most certainly does not supply the current user's current IP address to anyone on the network who asks for it. This would be a grossly unacceptable violation of privacy.

I really do not see how a workable IP telephony system could be developed from the description provided in the article. There must something else being planned here since the article's described system simply cannot work.
boozoo 12/4/2012 | 11:42:04 PM
re: P2P & VOIP: Coming Together? Sorry, my observation was not explain well enough.

My point was that the less routing info embedded in an address, the more serious are the scalability issues of the routing infrasturcture, especially if you want to include mobility in the equation.
I believe this is the main problem that Niklas Zennstrom from Kazaa is facing.


Your observation related to the toll free numbers and mobile numbers confirms the above statements. I bet that for every toll free number there's at least one entry in at least one database that statically maps that toll free number to a geographicaly-bound number. In other words, state information.
Try calling a north american toll-free number from europe and see what happens.


Mobile numbers are in essence similar, maybe slightly more complicated I think, because the location of the cell phone is more dynamic.
Plus, roaming is an expensive add-on service and I'm not sure if the problem of IP address mobilty has been satisfactory resolved.


cheers,

Boozoo

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