Tuesday, August 21, 2007

Internet Disruptions: Skype, Microsoft and Shotguns

On Thursday, August 16, Skype users experienced a critical disruption. The disruption was the result of a massive restart of Skype user computers around the world within a very short period of time. The reboot was the result of a series of Microsoft update patches that required a reboot. According to the Skype press release:

"The 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".

The press release continues:

"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.

This disruption was unprecedented in terms of its impact and scope. We would like to point out that very few technologies or communications networks today are guaranteed to operate without interruptions".

I've been away on vacation and have not been as connected as I usually am - as a result the outage did not really affect me. I do use Skype frequently and if I had been in the office it would have caused some problems. I find it interesting, and a little disturbing, that one of the first things Skype clarifies in the press release is the fact that the outage was not caused by any "malicious activities".

On Monday there was another incident that caught my attention - someone has been shooting (with a gun) fiber optic cables in the Cleveland area. As a result, Internet service providers in the entire country experienced a slowdown. You can read the Network World gunfire piece here. Here's a couple of quotes from the piece:

TeliaSonera AB, which lost the northern leg of its U.S. network to the cut, said that the outage began around 7 p.m. Pacific Time on Sunday night. When technicians pulled up the affected cable, it appeared to have been shot. "Somebody had been shooting with a gun or a shotgun into the cable," said Anders Olausson, a TeliaSonera spokesman.

The company declined to name the service provider whose lines had been cut, but a source familiar with the situation said the lines are owned by Level 3 Communications Inc.

Within the last week we've had both upper layer and physical layer major Internet disruptions. It certainly makes me think twice about our communications vulnerabilities.

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