A push notification provider is an application written by the application's developer to send push notifications to the iOS application through the APNs. Here are the basic steps to send push notifications to your applications via the APNs server:
The APNs is a stream TCP socket that your provider can communicate with using a SSL secured communication channel. You send the push notification (containing the payload) as a binary stream. Once you are connected to the APNs, you can send as many push notifications as you want within the duration of the connection.
NOTE Refrain from opening and closing the connections to the APNs for each push notification that you want to send. Rapid opening and closing of connections to the APNs will be deemed a denial-of-service (DOS) attack and may prevent your provider from sending push notifications to your applications.
The format of a push notification message looks like Figure 19-24 (taken from Apple's documentation).
NOTE For more details on APNs, refer to the Apple Push Notification Service ...