On the server, AdaptivePush™ is enabled for a client device.
The client receives the new setting at next synchronization.
In response to the new setting, the client initiates an HTTP connection to the server. This connection must be over a separate port from the port used for synchronization (which is 5011 by default). The default port used for network push is 5021 (6011 in DME 2.0).
When initiating the connection, the client receives any commands that are ready for the client - such as e-mail sync commands, settings, or other commands, over the GPRS network.
The client does not break the connection, but keeps it open.
However, the connection may be broken due to network problems, flight mode situations, or if the device is shut off.
The server tests whether the connection is still open according to a schedule of sign-of-life signals. First, a signal (an HTTP packet) is sent after one minute. Then, three packets are sent at intervals of 3 minutes. Then, five packets at intervals of 5 minutes. This scheme of ever-increasing intervals continues until a sign-of-life signal is sent every 30 minutes. The packet which is sent from the server contains information about when the server will contact the client again.
If the server does not contact the client after the specified period of time, the client tries to reconnect to the server every minute for 10 minutes before giving up.
When the client is turned back on or the network connection is restored, the HTTP connection with the server is also restored. Until then, the server pushes new e-mail commands and other commands by means of SMS messages (or, in the case of iPhone, possibly using APNS).
If, for some reason, the network push functionality is turned off on the server, the server tells the client to shut down the connection, and resorts to SMS push again.
To set up the server to enable network push, enable the setting Network push active, and configure the Network push path in Settings (see General settings).
For each resource in the notification framework, you can set up whether to use network push only or adaptive push (that is, with fallback to notification by SMS). See Notification.