Skype: What kind of infrastructure changes has Microsoft made?

It's been one year since Microsoft announced plans to acquire Skype and seven months since regulatory bodies approved the transaction, enabling Microsoft to take control officially of the VOIP vendor.

According to Ars Technica, Microsoft already has made some significant tweaks to the back-end Skype infrastructure, "replacing peer-to-peer client machines with thousands of Linux boxes that have been hardened against the most common types of hack attacks." Ars is basing the report on a security researcher's findings; he claims the change happened two months ago.

I wondered last year if and when Microsoft would put its stamp on Skype's back-end systems. With prior acquisitions, Microsoft sometimes lets newly acquired companies continue to run the same hardware, software and services they've been using before a Redmond take-over. Usually, over time, however, Microsoft tends to try to align the infrastructure of companies they acquire with the rest of the servers powering the company's other business units.

Hotmail is a classic example. The Hotmail servers were running FreeBSD for years after Microsoft began attempting to move them to Windows 2000.

Shortly after Microsoft acquired Skype, I asked a company spokesperson if and when Microsoft planned to change Skype's infrastructure and development methodologies. It was obvious from the Microsoft Jobs listings that Skype was using lots of PHP, Perl, Python and open-source. Would it ever make sense, for example, to move any Skype services to Azure? Or to try to convert Skype into a .Net shop?

I was told it was too early to say.

In July 2011, Skype execs said they were buying up some kind of servers for their datacenters to help maintain bandwidth for Skyping via Facebook, but they never specified which operating systems they were running.

I asked again today whether the Softies would comment on the latest report on changes coming to Skype's back-end infrastructure. So far, no response.

Update: Via a Microsoft spokesperson comes a response which seems to me to corroborate Ars' report (at least in part):

"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 datacentres. 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," according to Mark Gillett, Corporate Vice President, Skype Product Engineering & Operations.

Microsoft didn't respond as to whether these supernodes are now Microsoft-hosted Linux servers. Company officials also didn't respond to my question as to when the change in infrastructure occurred.

A quick search on the Microsoft Jobs boards indicates that Skype is still pretty much a PHP, Perl and Python shop. One open Skype job specified that either Linux or Windows experience would be acceptable.