Push server configuration

NexJ applications may require the application server to send or push data to the client in real time as it becomes available. For example, with a telephony integration solution, an incoming phone call triggers an event on the application server that notifies a user of an incoming call and loads details into a workspace about the contact who is calling.

To meet the needs of scalability, compatibility with different J2EE containers, and reliability of data, the push notification functionality is separated into two components: the push server and the push redirector.

The push server receives initial client requests, authenticates them, and redirects them to the push redirector.

The push redirector establishes a regular HTTP connection with the push server and listens for notifications coming in on the connection. After clients are authenticated and redirected by the push server, the push redirector establishes a Comet connection with clients and pushes notifications onto that connection. The push redirector is deployed on NexJ Server.

Comet is a communication technique that allows a server to send data to a web browser without the data being explicitly requested by the client. Data streaming and long polling are Comet modes. The push redirector also uses Comet in combination with Java NIO (non-blocking I/O) to disassociate threads from open sockets, creating a scalable push solution.

Note: For architectural information about the components in the push notification process, and notification protocols and modes, see Push notification architecture overview.