Understanding Push Notification

Push notification relies on the MPNS to dispatch notifications to the phone. The process works like this:

1. A phone app requests subscription to the MPNS using a notification channel.

2. The MPNS returns a URI, where notifications can be sent.

3. The phone app forwards the URI to any third-party service (such as a web service created by you) that wants to send the phone app notifications (see Figure 15.1).

FIGURE 15.1 An app subscribes to the MPNS, which is then forwarded to a third-party server.

The Push Notification URI is the address of the MPNS plus an identifier for phone device. Having received the push notification URI, a third-party service is then able to send notifications to the phone, via the MPNS, as shown in Figure 15.2.

FIGURE 15.2 Your server sends a notification to the MPNS, which is then forwarded to the phone.

Notifications from the cloud service use a well-defined protocol for sending notifications to the MPNS. Subsequent sections of the chapter examine the protocol format for the various notification types.