Push notification - usage of URI

Question

I create app for Windows Phone 7 and need to use push notification (toast).
To communicate between mobiles and server I will use channelURI from HttpNotificationChannel class. In mobile application in MainPage constructor I send channelURI to server. Server have list of some channel URI's and every hour send notification to mobiles with URI from list.

My questions are:
1) How long URI address will live with standard usage of phone? (How often application could be turn on and off?
2) Is some other, better method to resolve my problem?

Answer 1

I find answer for my first question. URi is valid for 30days.