Push Notifications

Apple and Windows mobile operating systems have restrictions on which applications can run in the background of the operating system. With this restriction in place, both Apple and Microsoft provide a hosted service that enables developers to deliver push notifications to devices. These notifications are used to notify users of application activity even when the application is not open, such as receiving an instant message (IM). The latest versions of Microsoft and Apple mobile operating systems enable VoIP applications to run in the background for the purpose of receiving calls. For the Lync 2013 clients that will be delivered after the initial release of Lync Server 2013, it is assumed that these clients will take advantage of that functionality and the Push Notification Service will still be used for instant messaging notifications.

In Lync Server 2010 and 2013, push notifications are delivered to mobile devices through a federated connection to the Microsoft Push Notification Clearing House. This service lives in the Office 365 cloud service, and acts as an intermediary between a Lync Server deployment and the Apple and Microsoft Push Notification Services for mobile devices. Organizations that want to enable push notifications will federate with the Office 365 service specifically for push notifications, and the MCX service will deliver push notification requests to that service.

When a mobile client registers and push notifications are enabled, the MCX service also registers a push notification identity for that user. The state of that user is maintained in the MCX service, and when a message is sent to that user, the MCX service initiates a request to the unique push notification ID, ultimately ending up at mobile endpoint as a notification. The details of this process are outlined in the following section.