Aron responded to a post Om wrote today about the Skype outage. Om's post is entitled, Does Skype’s outage indicate a fatal flaw in using Peer-to-Peer?"
Peter notes Aron's key point is that Skype's Peer-to-Peer model suffers from flaws not present in other Peer-to-Peer models (so it is Skype-specific vulnerabilities that are exposed by its ongoing outage, rather than vulnerabilities to Peer-to-Peer in general).
Here's Peter's deeper drilldown on Aron's key points:
According to Aron, like its predecessor Kazaa, Skype uses a different type of Peer-To-Peer network than most companies. Skype uses a system called SuperNodes. A SuperNode Peer-to-Peer system is one in which you rely on your customers rather than your own servers to handle the majority of your traffic. SuperNodes are just normal computers which get promoted by the Skype software to serve as the traffic cops for their entire network. In theory this is a good idea, but the problem happens if your network starts to destabilize. Skype, as a company, has no physical or programmatic control over the most vital piece of its product. Skype instead is at the mercy of and vulnerable to the people who unknowingly run the SuperNodes.
This of course exposes vulnerabilities to any business based on such a system -- systems that, in effect, are not within the company's control.
According to Aron, another flaw with SuperNode models concerns system recovery after a crash. Because Skype lost its SuperNodes in the initial crash, its network can only recover as fast as new SuperNodes can be identified.
Other companies such as SightSpeed that use Peer-to-Peer do not suffer from this fatal flaw, since these companies manage and handle all the core functionality themselves. Standards based telephony protocols such as SIP (which SightSpeed uses) were designed from the outset to be fault tolerant.
Yes, there are several flavors of P2P, and all P2P shouldn't be tarred with the same brush.