How to manage android service?

How does Parse manage sending notifications for Android devices?

• How does Parse manage sending notifications for Android devices? Parse blog says: "Our system isn’t dependent on C2DM, so it works on Android 1.5, 1.6, and 2.1, and doesn’t require a user to have an active Google account." from here http://blog.parse.com/2011/07/25/android-push-notifications/ I am wondering how they exactly do the notification to Android? If long pull, it costs data and battery of device.  Or their own solution? It costs Parse a lot to maintain. On top of what existing (open source) frameworks or purely developed by Parse engineers? Can some one explain what is under the hood? Thank you!

• Answer:

  At Parse, we decided to build our own push notification service so we could support older clients, people who preferred not to use C2DM (GCM was not yet available), and devices like the Kindle Fire which do not have access to C2DM/GCM. The client-side library is a long-polling TCP socket, which Java supports reasonably well out of the box. It's implemented as a true kernel-blocked long-poll, rather than a polling loop, to save battery life. This is the best practice whether written by Parse, Google, Apple, or Amazon. The backend does the heavy lifting. We keep costs down by building as much on top of open source platforms as possible. We use a variety of open source technologies at Parse, including Rails, Resque, EventMachine, MongoDB, Redis, etc.