Microsoft begin rolling out Windows Phone 7 update slowly out to users -- has raised following two hot questions in the technical community: How does my phone know when an update is available? How does Microsoft differentiate my phone from others that have received the update?
As you may know, there're two ways to determine if an update is available. Your phone can either notify you via its internal, scheduled check (Settings -> Phone Update) or you can request an immediate status via the Zune client (Settings -> Phone -> Update).
In both cases, the phone (not the Zune software) securely communicates with the familiar Microsoft Update services (update.microsoft.com) via the Windows Update Services protocol. (It's cute the Zune software tells the phone to check for updates, which it does… by looping back through the Zune pass-through connection.) In order, the phone:
- … checks for Microsoft Update (MU) services location, if cached location is stale
- … gets the configuration of MU [details]
- … gets a token for MU service communication, if one isn’t cached [details]
- … syncs update information with MU [details]
Refere this documentation Windows Server Update Services (WSUS) for more information.