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Reason behind Skype outage revealed

Reason behind Skype outage revealed

Thanks, but I think I'll stick to my mobile for now.

During the latter part of last week, Skype users has difficulty connecting to the Skype network. It all started last Thursday when the network started becoming sluggish before finally collapsing.

Skype's Heartbeat status blog says that the initial trigger behind the failure was a massive amount of users rebooting their computer after receiving a routine Windows Update.

The high number of reboots had an effect on the network's resources which then caused a flood of log-in requests. Combined with a lack of network resources, the situation snowballed until the system just crashed completely.

"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," said Skype's spokesman Villu Arak.

The bug has been squashed now, so if there's another outage at least it won't be caused by something as simple as a forced reboot on thousands of users at once.

Did the outage effect you over the latter part of last week? Have you moved over to using VOIP exclusively? Tell us what you think about the outage and VoIP services in general over in the forums or in the comments section below.

6 Comments

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slugs 21st August 2007, 09:15 Quote
thats the issue with building a system around users and relieing on peer to peer.

it does seem appauling they don't have some central infrastruture to under pin the network.
naokaji 21st August 2007, 09:17 Quote
Quote:
Originally Posted by slugs
thats the issue with building a system around users and relieing on peer to peer.

it does seem appauling they don't have some central infrastruture to under pin the network.

well.. thats the reason how they can provide people with free to dirt cheap calls...
riggs 21st August 2007, 09:31 Quote
I only use it at work, and not that often. It seemed to be on and off for a couple of days...
antiHero 21st August 2007, 09:49 Quote
I use it to talk to my parents in Germany and had to use my mobile for some days which costed a fortune.
Hope thats not happening any time soon again
mclean007 21st August 2007, 10:18 Quote
Quote:
Originally Posted by slugs
thats the issue with building a system around users and relieing on peer to peer.

it does seem appauling they don't have some central infrastruture to under pin the network.

They do - users log in to a the service via Skype's servers, which track users, maintain accounts, connect calls etc. These are relatively low bandwidth requirements compared to the actual audio streams in a call, which are routed directly from peer to peer. If Skype had to route every call through its own servers it would need an astronomical amount of bandwidth, and would also add latency - not something you want on a voice call.

It seems that what happened was a failure of the central infrastructure due to unexpectedly high demand for login services.

Why do you say "thats [sic] the issue with building a system around users and relieing [sic] on peer to peer"? A key advantage of peer to peer is that it removes the single point of failure. Some peer to peer networks, like Skype, function in a way that requires a central hub, and it is usually the central hub (as in this case) that causes problems, because the failure of a single peer is not fatal to the operation of the network. Other networks that operate in a mesh configuration, with no single point of failure, are phenomenally robust, much like the internet itself - servers can collapse, data cables are severed by workmen, whole cities can lose power and yet the internet just re-routes and carries on, with only the users whose direct physical link is lost being affected.

It's a bug in a service caused by unprecedented circumstances. It happens all the time - you can't test every possible combination of events before releasing software to users. Skype offers its service for free, and has fixed the bug. You can't really say fairer than that so I don't think there's any reason to complain about a two day intermittent outage.
DXR_13KE 21st August 2007, 12:52 Quote
i use skype and i like it, those days were it was out is nothing compared to what happens to telephones, water, energy and other internet messaging applications that fail randomly and sometimes takes a lot of time to bring them up again.
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