Skype, the peer-to-peer Voice Over Internet Protocol (VoIP) service yesterday suffered a major outage resulting in widespread disruption.

The Skype status page quickly reported a software issue that meant that users were unable to login, with a possible time-to-fix of up to 24 hours.

Signs of a major problem became evident in the forenoon (Indian time) on Thursday although some users in London reported trouble even around midnight.

As a result many users were unable to connect to the network, meaning that services were effectively rendered unusable.

The service, at the time of filing this copy, is intermittent but unreliable.

According to Mark Main, senior analyst at Ovum, outages and quality problems with VoIP service providers are "sadly still too common."

"That Skype has gone so long without a prolonged problem is quite an achievement," Main said. "However, this event is probably Skype's biggest hiccup to-date, as it approaches its fourth birthday. Rather more worrying is the admission by Skype that it is an algorithmic problem - Skype always claimed scalability due to it peer-to-peer mode of operation. A problem with the peer-to-peer algorithm also makes it more likely that very large numbers of users have been affected at some point, although Skype hasn't yet been specific about the scale of the outage."

Main stated that while looking a bit deeper, there have been a few signs in recent months that possibly all is not well with Skype.

"One of my colleagues was on a conference call the other day dialling in via SkypeOut and he was barely audible. Chat sessions I have initiated recently on Skype have taken upwards of five - sometimes fifteen - minutes to deliver small amounts of text to users whose status was shown as Online. The difficulty analysing such problems is that all the evidence is anecdotal and certainly not based on a good statistical sample. That the user base continues to grow - albeit now at a slower rate - suggests that the overall user experience has been good enough, so far."