The Microsoft connection clarified

By Villu Arak on August 21, 2007 in News, events, milestones.

Hello all,

Yesterday, we posted an explanation of what happened to Skype on August 16. Some reactions to the explanation, however, have reminded us of one of the basic tenets of communication: It's not what you say. It's what they hear. We'd therefore like to clear a few misunderstandings that emerged in yesterday's reactions to our explanation of what transpired last week.

1. Are we blaming Microsoft for what happened?

We don't blame anyone but ourselves. The Microsoft Update patches were merely a catalyst -- a trigger -- for a series of events that led to the disruption of Skype, not the root cause of it. And Microsoft has been very helpful and supportive throughout.

The high number of post-update reboots affected Skype’s network resources. This caused a flood of log-in requests, which, combined with the lack of peer-to-peer network resources at the time, prompted a chain reaction that had a critical impact. The self-healing mechanisms of the P2P network upon which Skype’s software runs have worked well in the past. Simply put, every single time Skype has needed to recover from reboots that naturally accompany a routine Windows Update, there hasn’t been a problem.

Unfortunately, this time, for the first time, Skype was unable to rise to the challenge and the reasons for this were exceptional. In this instance, the day’s Skype traffic patterns, combined with the large number of reboots, revealed a previously unseen fault in the P2P network resource allocation algorithm Skype used. Consequently, the P2P network’s self-healing function didn’t work quickly enough. Skype's peer-to-peer core was not properly tuned to cope with the load and core size changes that occurred on August 16. The reboots resulting from software patching merely served as a catalyst. This combination of factors created a situation where the self-healing needed outside intervention and assistance by our engineers.

2. What was different about this set of Microsoft update patches?

In short – there was nothing different about this set of Microsoft patches. During a joint call soon after problems were detected, Skype and Microsoft engineers went through the list of patches that had been pushed out. We ruled each one out as a possible cause for Skype's problems. We also walked through the standard Windows Update process to understand it better and to ensure that nothing in the process had changed from the past (and nothing had). The Microsoft team was fantastic to work with, and after going through the potential causes, it appeared clearer than ever to us that our software's P2P network management algorithm was not tuned to take into account a combination of high load and supernode rebooting.

3. How come previous Microsoft update patches didn't cause disruption?

That's because the update patches were not the cause of the disruption. In previous instances where a large number of supernodes in the P2P network were rebooted, other factors of a "perfect storm" had not been present. That is, there had not been such a combination of high usage load during supernode rebooting. As a result, P2P network resources were allocated efficiently and self-healing worked fast enough to overcome the challenge.

4. Has the bug been fixed? Should Skype users worry about future Microsoft Update patches and reboots?

Yes, the bug has been squashed. The parameters of the P2P network have been tuned to be smarter about how similar situations should be handled. Once we found the algorithmic fix to ensure continued operation in the face of high numbers of client reboots, the efforts focused squarely on stabilising the P2P core. The fix means that we've tuned Skype's P2P core so that it can cope with simultaneous P2P network load and core size changes similar to those that occurred on August 16. We’d like to reassure our users across the globe that we’ve done everything we need to do to make sure this doesn’t happen again. We’ve already introduced a number of improvements to our software to ensure our users will not be similarly affected – in the unlikely possibility of this combination of events recurring.

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Comments

It seems that Micro$oft has hit again.

Well, no. Thats the point of the whole post. Also, this dollar $ign thing is getting old ...

Hi Skype,

Just received the email notice of the extension of my services because of the outage last week. I appreciate you so quickly providing fair compensation for the time my paid services were unavailable. I have used Skype for two years now, and this was the first time I ever had a problem with it. I know everyone worked long and hard to resolve the issue, and to do the right thing for your customers. You have done a great job with both, and so, Thanks!

I think you guys are doing us all a great service nothing is perfect in this world and only to be down for 2 days in the last 3 years i have used skype than that is better than my phone & internet companys keep up the good work , A very happy Skype pro customer

I am a user skype from 2 years ago. I am from Bucharest-Romania-Europe. The quality of sound and video are the best. This 2 days problem was verry small and i wish good luck in future for the skype team. Please do something with people user skype in Romania. The price for callig are high and connecting with land line phone price are high.
Thanks

I would like to know where or at which country, the problem came about.

I am brand new to this Skype thingy and let me tell you...after reading the current postings I have to say that if in 3 years there was only 2 days of downtime...?? I come from the cellular industry and I know what real downtime is, what happened is not real downtime. Furthermore, for mere cents per minute for out-calling we should all be fanatical for this service, regardless. I am saving sooo much by converting to Skype and am glad to say good riddance to the corporate greed of ALL the cellular companies. I just hope that Skype can maintain this inexpensive mode of communication and the rest of the world comes aboard! The cellular company I worked for uses Internet Phonage technology for their entire inbound call center sites across the US (which surprised me because I never suspected) and Skype's service is as clear as their's and apparently more stable. I tell everyone about Skype now! All Hail!

Thanks for giving a detallied explanation of what happened, I also received an email extending my skypein subscription, which I thank very much, not for the 7 days, but for the preocupation you guys demonstrated for customers like us.

Just a quick note to thank you for the free time you have extended us all. That goes above and beyond the call. I do have a question for anyone . . .I am totally new to Skype and am wondering if there is a booklet or something to read that will tell me what and how to do things. Donna

So, so sorry - I hit post 3 times obviously - had no idea it would post so many times. You see, I really need a manual . . .

Thanks for all the comments and support. It's heartwarming to see that we have real friends around the world who've stood by us through good times and bad.

Hallo dear,