Android – Does Android support near real time push notification

I recently learned about the ability of iPhone apps to receive nearly instantaneous notifications to apps notifications to apps.

This is provided in the form of push notifications, a bespoke protocol which keeps an always on data connection to the iPhone and messages binary packets to the app, which pops up alerts incredibly quickly, between 0.5 – 5 seconds from server app send to phone app response time. This is sent as data – rather than SMS – in very very small packets charged as part of the data plan not as incoming messages.

I would like to know if, using Android, there is either a similar facility, or whether it's possible to implement something close to this using Android APIs. To clarify, I define similar as:

• Not an SMS message, but some data driven solution
• As real time as is possible
• Is scalable, i.e., as the server part of a mobile app, I could notify thousands of app instances in seconds

I appreciate the app could be pull based, HTTP request/response style, but ideally I don't want to be polling that heavily just to check for notification; besides which it's like drip draining the data plan.