Skype Says Bug in Older Software Caused Outage

Skype offered a detailed explanation Wednesday for the "critical failure" that prevented millions of Skye users worldwide from placing or receiving calls last week. According to the VoIP (Voice over Internet Protocol) operator, a bug in an older version of the Skype for Windows client software caused 25 to 30 percent of the service's supernodes to fail.

Like any other peer-to-peer network, Skype relies on supernodes with the ability to take on additional responsibilities compared to regular nodes by acting like a directory, supporting other Skype customers and creating local clusters, noted Skype CIO Lars Rabbe.

Supernode has failed

"Once a supernode has failed, even when restarted, it takes some time to become available as a resource to the P2P network again," Rabbe wrote in a blog. "As a result, the P2P network was left with 25 percent to 30 percent fewer supernodes than normal," which caused "a disproportionate load on the remaining available supernodes."

To recover the core system functionality as quickly as possible, Skype utilized resources on the whole dedicated to supporting group video calling, using them to deploy supernodes, Rabbe explained. "Over the course of Thursday night and Friday morning, we returned these to their normal use and restored group video calling functionality in the course of time for Christmas," Rabbe explained.

The service disruptions that occurred at Facebook

Online outages are inevitable -- as the service disruptions that occurred at Facebook, Twitter and Google's Gmail service have already demonstrated this year. After all, Skype's latest snafu came as an unpleasant pre-Christmas surprise for many business users, which Di Maio found surprising.

"For some mysterious reason, we seem to believe that the Internet and -- furthermore -- the cloud [will] shield us from painful experiences, now that's not the case," Di Maio noted.

Users need to ask themselves to what extent they can personally or professionally rely on online tools over which they have no control or oversight, Di Maio advised. "We all need to as a matter of fact understand that innovation is fallible and we will always need to exercise our creativity to react to unexpected situations," he wrote.

Di Maio as well advised online service providers to leverage their critical failures as learning experiences, which is precisely what Skype is promising to do. "Lessons will be learned and we will use this as an possibility to identify and introduce areas of improvement to our software, furthermore assess and invest in capacity and stability, and develop better processes for outage recovery and communications to our user base," Rabbe explained.

Given that Skype's outage was caused by outdated software, the network operator will be providing users with furthermore software updates this week as then as reviewing its automatic software update processes to ensure that all users are running the latest releases. "We believe these measures will reduce the opportunity of this type of failure occurring again," Di Maio added.

Moreover, Skype intends to look for new ways in which the online service can detect potential problems more quickly as so then as recover more rapidly following any system failure. Additionally, the VoIP provider will be reviewing its testing processes "to determine better ways of detecting and avoiding bugs which could affect the system," Di Maio wrote.