Skype Blackout Fixed, Caused by Massive PC Restart

Microsoft Windows patches and millions of PC restarts cracked Skype.

The blackout that left millions of Skype users without the ability to make Internet phone calls from their PCs for two days was, ironically, triggered by the services users.

Skype offers a P2P (peer-to-peer) VOIP (voice over IP) software service, which allows users to make phone calls, instant messages and videos over their computers with a broadband Internet connection. The service is free for users of the Skype network and is extremely popular, boasting more than 220 million users.

Skype spokesman Villu Arak wrote in a blog post Aug. 20 that the outage, which was resolved Aug. 18, happened after a massive restart of its users computers across the globe as they "re-booted after receiving a routine set of patches through Windows Update."


Click here to read more about the Skype outage.

Arak said the high number of restarts in a short time period clogged Skypes network, causing a flood of log-in requests. These, combined with the lack of peer-to-peer network resources, "prompted a chain reaction that had a critical impact."

"This disruption was unprecedented in terms of its impact and scope," Arak said.

While Skypes P2P network does have the ability to fix itself for just such problems, Arak said the outage revealed a software bug within the network resource allocation algorithm that prevented the self-healing function from properly working.

This bug was not, he said, created via malicious activity. Moreover, Skype users were not at risk to security threats, Arak claimed.

Arak added that Skype has augmented its software so that its users will not suffer from an outage in case this problem happens again.

Still, some damage to the companys perception may have been done, considering that several businesses rely on Skype for their communications.

"In terms of Skypes image in the marketplace, especially as more enterprises have started to consider the service [e.g. for remote workers or road-warriors], a large-scale, relatively long-term outage could have detrimental effects to what otherwise could have been a growing portion of their business," Forrester Research analyst Sally Cohen said.

VOIP providers and some enterprise software makers see the real sweet spot for success in hooking up businesses with VOIP access. IBM, Microsoft and Oracle all support VOIP in their collaboration software packages.

But overall VOIP needs some serious improvements before it can infiltrate the mainstream market. For one, the call quality of VOIP services has generally not been as good as that of traditional phone lines.

Also, call completion rates are low thanks to the NAT (Network Address Translation) protocol, which involves rewriting the source or the destination addresses of IP packets or both as they pass through a router or firewall.


Click here to read more about Skype and whether its ready for prime time.

Regardless of these challenges, Skype competes with services from market leader Vonage, as well as services from incumbent communications carriers Verizons VoiceWing and AT&Ts CallVantage service.


Check out eWEEK.coms for the latest news, reviews and analysis on mobile and wireless computing.