Skype and Facebook on Wednesday announced that they had integrated video calling into the social network. By doing so, Facebook and Skype create the world's largest community of people who can communicate between each other using the social network or Skype technologies.

"At Skype, we are super excited about this product, which we closely collaborated with Facebook on many of the parts of the solution in a true team effort. We think users will love its ease of use and simplicity. It combines the quality and scale of Skype video calling with the social experiences of Facebook in a way that we believe makes for a powerful combination," said Jonathan Rosenberg, chief technology strategist at Skype.

While looking at the one's profile page on in Facebook or while in a chat, users will now see buttons which allow them to initiate a video call with their friends. Those buttons are rendered as part of the Facebook web page. When a user clicks on the "call" button, the page will check for the existence of the Skype video calling software, which is an optimized version of Skype's plug-in that powers the video calling.

Facebook's servers interact with Skype's technology through a proprietary REST API developed by Skype. Through that API, Facebook automatically creates an anonymous Skype account for new callers (or 'callees'). The REST API also allows Facebook servers to obtain a login credential that can be used to log the user into Skype using the anonymous account.

The plug-in is in essence, a miniature version of the Skype client. The plug-in is actually composed of two distinct parts. One is the runtime, which is a standalone miniature Skype client, and the other is an actual browser plug-in. The runtime provides some simple APIs through an RPC mechanism, and the browser plug-in delivers those APIs in JavaScript for access within facebook.com. Despite its compact size and simplified UI, the runtime is Skype in all ways that matter, according to the chief technology strategist. Skype's peer-to-peer technology, our firewall and NAT traversal protocols, our video and audio codecs, our media processing engine - everything that makes Skype wonderful - is there, in the runtime.

Once the plug-in has been downloaded and installed, and the caller logged into it anonymously (a process which happens automatically), a handshake takes place through Facebook's server infrastructure. This handshake alerts the 'callee' that the caller wishes to call them. By using Facebook infrastructure for this, Skype allows calls to be initiated prior to installation of a plug-in on the callee's computer. The user interface you see for the video itself is rendered by the Skype runtime, hence, the quality should be the same.

"One of Skype's challenges in providing this functionality was scale. Even though Skype leverages its P2P technology to help achieve scale, we still rely on server infrastructure for several parts of the solution. To handle all of this, Skype has substantially increased server counts and added bandwidth in all of our data centers. The actual voice and video traffic utilizes Skype's global P2P network, allowing for great quality without needing thousands of expensive servers," added Mr. Rosenberg.

Tags: Skype, Facebook