Re: [wg-pic] Tolly's Skype critique

[Kewin Stoeckigt <>]

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Hi,
there is a paper available from Henning Schulzrinne and Salman Baset at
http://arxiv.org/pdf/cs.NI/0412017 which describes some of the traffic.
The paper is called 'An analysis of the Skype peer-to-peer Internet
telephony protocol'. Its an interesting document which gives a very
detailed overview. But this is basically everything what you can find. I
know that some one at the University of Melbourne is working in that
area, and that the company Metanetworks is working on it as well.

Kewin

Doug Pearson wrote:
> Anyone have a good reference to the inside technical details of how Skype 
> works? 
> 
> The Tolly article says "dearth of information available to us, we learned 
> most of what we know by studying Skype 'in the wild'"... but it doesn't 
> share much about those details.
> 
> Doug Pearson
> 
> 
> At 04:01 PM 9/29/2005 -0400, Ben Teitelbaum wrote:
> 
>>Candace Holman 
>><>
>> writes:
>>
>>
>>>In this article, Tolly studied Skype peer-to-peer traffic to evaluate
>>>the impact on network bandwidth.  He quoted the Skype Web site on what
>>>peer-to-peer means: "A true [peer-to-peer] system, in our opinion, is
>>>one where all nodes in a network join together dynamically to
>>>participate in traffic routing-, processing- and bandwidth-intensive
>>>tasks that would otherwise be handled by central servers." Interesting
>>>view.  Tolly suggests that this means your Skype-enabled workstation
>>>may be functioning as a traffic relay for otherwise-centralized call
>>>processing, conferencing, voice mail, etc.  
>>
>>That seems like a fair definition of "true peer-to-peer" to me.  One
>>of the big reasons that universities may see a lot of Skype traffic is
>>the use of public IP addresses.  Skype needs a share of its users to
>>be non-NATted to serve as media relays for hosts behind
>>tricky-to-traverse NATs.
>>
>>-- ben
>>
>>-- 
>>Ben Teitelbaum   http://people.internet2.edu/~ben/
> 
> 


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