User Notification is the first aspect of cloud push that you must understand. When a user is actively working with an application on a mobile device the user interface (UI) of that application can continually update information displayed to the user as the state of the application changes. For instances, an email application can update the number of emails in the inbox as new emails arrive. When the user is not actively using an application, that application can not rely on its UI to convey new information to the user because the UI is not visible at the moment. Mobile devices provide a number of ways to alert the user of a state change occurring in an inactive application. A status bar can display an alerting icon, or a sound or vibration can occur. For instance, an email application can display an icon indicating that new mail has arrived since the user last viewed her inbox.
When a user notification is the result of some state change coming from outside the device over a network connection, we refer to that as Cloud Push. The dominant mobile platforms all provide Cloud Push mechanisms that can be incorporated into an application. Specifically the mechanisms are:
These mechanisms can be integrated directly with a native mobile application to achieve appropriate user notifications triggered from the network cloud.
Beyond these proprietary push mechanisms, other common network protocols can be considered for cloud push notification, such as:
- SMS text messaging
These mechanisms have the advantage of ubiquitous support across mobile platforms, relying on the device's built in support for these protocols, but won't necessarily integrate tightly with the native application.