My Research - Push Notification in Mobile Ecosystem in 2011 - What Part 2

What is it?

Push, or server push, describes a style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server. It is contrasted with pull, where the request for the transmission of information is initiated by the receiver or client.[WikiPedia]

For ages, Telecom technology SMS is being used for Push notification, its smpp protocol on SS7 networks. Email is also kind of Push Notification using SMTP.

Blackberry or RIM is using it for longtime for Email Notifications while Apple generalized it Now Android and Nokia are trying put their foot forward to enhance its usage. It primarily runs using HTTP/TCP/IP network protocol.

Genaral Use

Push services are often based on information preferences expressed in advance. This is called a publish/subscribe model. A client might "subscribe" to various information "channels". Whenever new content is available on one of those channels, the server would push that information out to the user. [wikipedia]

Techniques

HTTP Push Server:

HTML5 is the WebSockets API, which allows a web server and client to communicate over a full-duplex TCP connection.

Pushlet

The server takes advantage of persistent HTTP connections and leaves the response perpetually "open" (i.e. it never terminates the response), effectively fooling the browser into continuing in "loading" mode after the initial page load would normally be complete.

Long Polling

Long polling is a variation of the traditional polling technique and allows  emulation of an information push from a server to a client.(comet programming)

SMS

Andriod application can read all received SMS before it goes to inbox.

WebSockets

HTML5 browsers

Mobile OS/Phone leaders are providing Push notification built into their offerings.