Windows Live Messenger is used on a daily basis across the world. Following the instant messaging partnership between Yahoo and Microsoft, Windows Live Messenger has only increased in popularity. But Live Messenger is only the surface of Microsoft's IM service. And Zack Whittaker, a Microsoft contract employee, has explained the Messenger Relay system. The graphical representation included at the bottom is courtesy of MSBlog.

A message initiated in Windows Live Messenger will reach its destination, after traveling a minimum of two times around the globe, within two seconds of initiation. The actual process involves a Windows Live ID Credentials server to verify the user's Windows Live ID credentials. The resulting data advanced to the first coordinate of connection, a dispatch server via an incoming firewall.

"Depending where the user is in the world, a connection will be made to the local notification server. There are main ones in Singapore, Dublin, Redmond and Reading. This keeps the connection between the two users alive, and keeps things updated such as user status, chat requests and email notifications from Windows Live Mail/Hotmail," revealed Whittaker.

The switchboard servers centralize the exchange of messages, file transfers and video and audio connections. The actual swap of content is done exclusively via switchboard sessions.

"The information is then relayed back through an outgoing firewall and checks the user is still online. If the user is offline by the time the message is ready to be received, then it'll bounce back and be saved on the switchboard session until the user logs back on again. If they are online, they will receive the message," added Whittaker.