How device receives push notification? - iphone sdk

I want to ask you guys How device receives push noti开发者_开发技巧fication? Is our device continuously connected to apple's server?

Many Thanks,

Nav

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Device does not remain connected. In fact the app might not even be running any more.

The mechanism is as follows:

1. Your application has to register for notifications.
2. When it registers you get a token, which you send to your server.
3. When you wish to send a push notification, your server connects to Apple server and sends a message to the previously registered token.

Simple :)

For more details see: http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/ApplePushService/ApplePushService.html#//apple_ref/doc/uid/TP40008194-CH100-SW9