Presence Recovery

The presence-related services of an endpoint—the LocalOwnerPresence, ContactGroupServices, and PresenceServices properties—are references to, respectively, the LocalOwnerPresence, ContactGroupServices, and LocalEndpointPresenceServices classes. These services use several Microsoft Lync Server 2010 servers to publish and subscribe to presence data. For example, the User Services role of Lync Server 2010 is the repository of presence data, while the Front End service is responsible for routing publication and subscription requests. When any of the relevant Lync Server 2010 services goes offline or loses connectivity, the Microsoft Unified Communications Managed API (UCMA) 3.0 presence services are disrupted as well.

The UCMA 3.0 platform is able to detect several types of disruption, such as when a LocalOwnerPresence instance is unable to subscribe to its self presence, or when a RemotePresenceView instance is unable to add a new target. For registered endpoints UCMA receives a notification from the Lync Server 2010 server that User Services is unavailable. When UCMA learns of a disruption, the state of the affected service changes to WaitingForRetry. This causes UCMA 3.0 to retry the failed operation to recover from a temporary server failure.