Almost from the very day that Microsoft announced plans to buy Skype in 2011 , there have been questions about the service's underlying infrastructure. Today, July 20, 2016, Microsoft officials finally provided a bit more clarity about what's been going on under the covers with its Skype consumer service.
When Microsoft bought Skype, the service was entirely a peer-to-peer (P2P) one. In 2012, Microsoft developed supernodes and added them to Skype's P2P backbone. These supernodes, which were located on dedicated servers within secure datacenters, were meant to allow users to find one another more easily, company officials said at the time. They said calls were not routed through these supernodes.
Shortly thereafter, Microsoft started revamping Skype's backend to turn it into a cloud-hosted service -- a move which some watchdogs claimed Microsoft did to make accessing user data easier for police and intelligence agencies. Microsoft denied this was the reason for moving Skype to the cloud, but didn't say a whole lot more back in 2013 as to why it was undoing the P2P backbone of Skype.
Like many others, I bet, I had assumed Microsoft's work on moving Skype to the cloud was done by now. That isn't the case, however, said Gurdeep Pall, the corporate vice president in charge of Skype and Skype for Business.
There are still some pieces of Skype that are running on P2P, though Microsoft thinks it will be able to retire these services and go almost all cloud within the coming months, he said during an interview I had with him last week.
"Over the last ten years, things changed a lot. Multiple devices and mobile came along. Running P2P on mobile was not sustainable," Pall said.
"We started the transformation to cloud from P2P a couple of years ago. We've started our migration across chat, audio video, file sharing, identity. We now have a service that can meet affordances and constraints," he said.
Pall said that Microsoft has been supporting interop between P2P and cloud for Skype for the past couple of years, but "now the majority of our clients can be cloud only."
It was this interop stage that resulted in some of the Skype annoyances many of us know well: Instant messages arriving out of sync; messages not syncing properly across different devices; Skype calls ringing on multiple devices rather than just on the device in use, Pall said.
"We were rebuilding the plane while we were flying it," he quipped.
Recently introduced Skype features, like multiparty audio/video on mobile, Skype Translator, the Skype Bot platform, and file sharing are all running entirely on Skype on Azure and not P2P, Pall said. Support for some services that were built on the P2P stack, such as Skype for TV, is being discontinued, as Microsoft decided it was either impossible or not cost efficient to try to move them to Azure, he said.
Microsoft's goal is to have the media path the only piece of the Skype backbone that doesn't go cloud. For media, P2P will be the first choice, with Azure as the backup path. But the rest of Skype consumer will be all Azure, all the time, in the not-too-distant future, he said.
Microsoft's Skype for Business service, which is Microsoft's Lync service rebranded, wasn't built on the same infrastructure as Skype consumer. I asked Pall what Microsoft was doing to update Skype for Business' backend, but he said he had no comment at this time.
As part of today's disclosure on what's been going on with Skype, Microsoft also said that Skype consumer, going forward, would only work with certain, newer versions of Windows, Android, and iOS. The list includes Windows XP, Vista, 7, 8, and 10; Yosemite on Mac; iOS 8; and Android 4.03.