Push Services (like GCM): How do they do it exactly?

[KMatle]

Almost all phone providers prevent a phone to be contacted from the outside, but it must be something as a sender/listener construct. On the other hand, this is very complicated to keep running (billions of devices).

Does anyone know how they do it technically?

 

[Erel]

It is not a "real" push solution. The device keeps an open connection to Google servers. The advantage of GCM is that the connection is maintained by the OS and can provide the push messages to many apps.

 

[b4auser1]

http://stackoverflow.com/questions/11508613/how-does-push-notification-technology-work-on-android

From what I've heard during an Android developers conference in Israel:

There is simply a TCP socket waiting in accept mode on a cloud Google server. The TCP connection had been initiated by the Goggle Play application. That's why Google Play must be installed on the device for making Google Cloud Messaging (GCM) (formerly Android Cloud to Device Messaging Service - C2DM) work.

When this TCP client socket receives some message, the message contains information such as the package name of the application it should be addressed to, and of course - the data itself. This data is parsed and packed into an intent that is broadcast and eventually received by the application.

The TCP socket stays open even when the device's radio state turns into "idle" mode. Applications don't have to be running to receive the intents.

More information at http://developer.android.com/google/gcm/gcm.html

I believe that all the push services are based on this approach.

 

[b4auser1]

The advantage of GCM is that the connection is maintained by the OS and can provide the push messages to many apps.

+1

 

[somed3v3loper]

It is not a "real" push solution. The device keeps an open connection to Google servers. The advantage of GCM is that the connection is maintained by the OS and can provide the push messages to many apps.

Does this mean it is possible to create such service ?
I know it is better to use GCM but would like to see how it is implemented .

 

[Erel]

Yes.
Custom WebSocket Based Push Framework

 

[somed3v3loper]

Yes.
Custom WebSocket Based Push Framework

Yes it is a great solution but I think we need to keep starting client service module so we can receive push messages .
What do google use to make sure their service is always running ?

 

[Erel]

What do google use to make sure their service is always running ?

GCM is handled by the OS so it can make sure that the service is always running.