C2DM background technology

I need further information about C2DM on android. The informations on http://code.google.com/intl/de-DE/android/c2dm/inde开发者_StackOverflow中文版x.html are not clear about the background technology.

Which protocolls are used? How does the Google server find my cell phone?

I need such informations.

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You can get some info about C2DM internals from Google I/O 2010 video: Building push applications for Android

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C2DM maintains an open TCP socket connection to the messaging server. Its really rather simple, other than keeping the socket open, which is no exactly trivial.