Microsoft has replaced a major part of Skype’s network by replacing its 48,000 P2P supernodes with a set of centralized Linux boxes. This change was done over two months ago as a security measure. The Linux boxes are being hosted by Microsoft itself and this is the first such network change inside Skype, since it started operating in 2003.
The change has been analyzed by Kostya Kortchinsky over at Immunity Security. Microsoft is yet to confirm the research’s findings, but it has released a statement to Ars Technica saying,
As part of our ongoing commitment to continually improve the Skype user experience, we developed supernodes, which can be located on dedicated servers within secure datacenters. This has not changed the underlying nature of Skype’s peer-to-peer (P2P) architecture, in which supernodes simply allow users to find one another (calls do not pass through supernodes). We believe this approach has immediate performance, scalability and availability benefits for the hundreds of millions of users that make up the Skype community.
Microsoft has probably made this move to prevent outages like these. Currently, there are little over 10,000 supernodes, all hosted centrally by Microsoft. Unlike earlier, when users with sufficient bandwidth were upgraded to supernode status, the new strategy does not make supernodes out of users.
Seven months into ownership of Skype, and Microsoft is already making changes to it. Although it is not trying to port any existing infrastructure to its own technology stack immediately, there is a fair chance of that happening and when that happens, undoubtedly, Azure will be the way to go for Skype.
Read Kortchinsky’s report here.