Push notifications require an intermediary server between the app service provider and the device push provider, that's GCM. Your phone has a persistent connec

Push notifications require an intermediary server between the app service provider and the device push provider, that's GCM. Your phone has a persistent connection to it so that the GCM can "notify" your device when you receive a push. The alternative is to have a custom Android OS linked to your own push provider and then convincing app server developers to send pushes to that instead. Unfortunately, whether we like it or not, it's hard to get away from.