Skype weakness exposed by Microsoft

Stan Beer
Tuesday, 21 August 2007 05:53

Opinion and Analysis

The two-day outage of Skype last week has exposed a serious weakness in the company's networking system which has been made self evident by its own explanation of what took place. Skype's proprietary peer-to-peer networking system has through its own architecture become entwined with the actions of Microsoft.

In a nutshell, Skype relies on the collective power of the personal computers of more than 200 million users rather than its own servers. So when a large proportion of those users restarted their computers at around the same time last week the network suffered an unrecoverable crash.

The problem for Skype is that more than 90% of the world's personal computers run some version of Microsoft Windows as their operating system. That means it's a fair bet that at least 180 million or more Skype users run Windows.

At least once a month, Microsoft issues software patches to Windows users that require the users to restart their computers. That means within a short space of time almost 200 million computers on the Skype network shut down, restarted and tried to log back on to Skype.

It's not difficult to imagine the effect on a peer-to-peer network that has less than 10% of its normally available resources trying to cope with almost 200 million newly restarted computers trying to log on to Skype at the same time.

According to Skype, which outlined the reasons for the crash in its Heartbeat blog , its network resourcing software should have been able to cope with this situation but a bug was revealed that kept the network down. An unanswered question, however, is why after four years of regular Windows patching cycles did such a catastrophic unrecoverable network outage occur.

It may be that Skype is a victim of its own success and the success of Microsoft. In the past two years, the Skype network has more than doubled in size to an estimated 200 million - some say 220 million - users. With the vast majority of the network constituents being Windows users, the larger the Skype network grows, the more vulnerable it could become to mass restarts.

Skype states in its blog: "The issue has now been identified explicitly within Skype. We can confirm categorically that no malicious activities were attributed or that our users’ security was not, at any point, at risk."

It's good to know that our conversations are secure but many users who have come to rely on Skype as a key means of communicating may want to know what will happen the next time Microsoft issues a critical patch.