Devoted to hardware, software, IT issues, and information technology management

I promised I would follow-up with a post once Skype reported the root cause of their service outage and Villu Arak posted an explanation this morning on the Skype Heartbeat which provides status information on the service:

"The Skype peer-to-peer network became unstable and suffered a critical disruption.  The disruption was initiated by a massive restart of our user’s computers across the globe within a very short timeframe as they re-booted after receiving a routine software update."

Although they didn't give specifics and I'm not too familiar with how they deploy routine software updates or schedule reboots, I'm curious to know how much of a "very short timeframe" we're talking about here.  Did the global reboot occur within minutes or hours?  Considering that it is a global network and not all users computers were on at the same time, I assume this was more of a snowball effect than a single catastrophic event, but I'll let the explanation continue:

"The abnormally high number of restarts affected Skype’s network resources.  This caused a flood of log-in requests, which, combined with the lack of peer-to-peer network resources, prompted a chain reaction that had a critical impact.

Normally Skype’s peer-to-peer network has an inbuilt ability to self-heal, however, this event revealed a previously unseen software bug within the network resource allocation algorithm which prevented the self-healing function from working quickly. Regrettably, as a result of this disruption, Skype was unavailable to the majority of its users for approximately two days."

Skype reiterated that this was not the result of a malicious attack, but a bug in their software:

"Skype has now identified and already introduced a number of improvements to its software to ensure that our users will not be similarly affected in the unlikely possibility of this combination of events recurring."

I assume the software improvements won't initiate a global reboot or if it does, it won't have the same effect.  I've learned that in the past four years, people really like this product and have come to depend on it for personal and business use.  Skype probably put VoIP on the map for many and I hope they recover from this stumble.