Wednesday, August 22, 2007

Analysts Blame Skype for Massive VOIP Outage

"Skype and Microsoft engineers went through the list of patches that had been pushed out," Arak wrote. "We ruled each one out as a possible cause for Skype's problems. We also walked through the standard Windows Update process to understand it better and to ensure that nothing in the process had changed from the past (and nothing had)."

The catastrophic effect on Skype's service was entirely Skype's fault, a result of its software being unable to deal with simultaneous high load and supernode rebooting, according to Arak.






This much we know: Skype's two-day outage was triggered after its peer-to-peer network became disrupted following a massive restart of its users' computers as they rebooted after receiving a routine set of patches through Windows Update.


The blitzkrieg of restarts caused a flood of log-in requests, which led to a global bog down in service. In the course of the outage, Skype engineers discovered a software bug within the network resource allocation algorithm that prevented the service from righting itself.


So, is it Skype's fault or are the routine Microsoft Windows Update patches to blame? VOIP (voice over IP) experts believe Microsoft can't be blamed because service providers are supposed to be prepared for the regular updates the software power automatically deploys.



Skype's service relies on some of its users' computers to act as "supernodes," routing traffic for other, less well-connected, users. But as Skype customers tried to reconnect, many of those supernodes were themselves in the process of rebooting. The remaining supernodes were soon overwhelmed because a bug in the company's software did not efficiently allocate the network resources available.

Users were sceptical of this explanation, because Microsoft regularly issues patches that may cause Windows computers to reboot, and this has not caused problems for Skype before.






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Tags: analysts | Flood | Microsoft | Network | outage | patches | prepared | rebooted | SERVICE | Skype | update | voip | windows

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