Patent ID: 8279826

Claim:
One or more computer-storage media having computer-useable instructions embodied thereon for performing a method for providing presence based routing in an IP Multimedia Subsystem (IMS) network, the method comprising: receiving a request at an application server within the IMS network from a first endpoint in an enterprise network to deregister the first endpoint, wherein deregistering the first endpoint indicates to the IMS network that the first endpoint is no longer registered with the enterprise network, wherein the enterprise network utilizes a private branch exchange to route calls from the IMS network to endpoints within the enterprise network, and wherein the application server provides logic to process and direct calls as the calls leave the (IMS) network; within the IMS network, receiving forwarding data from the first endpoint, wherein the forwarding data indicates a second endpoint outside of the enterprise network to which future calls to the first endpoint are to be forwarded while the first endpoint is unregistered and until the first endpoint is registered with the (IMS) network; deregistering the first endpoint within the (IMS) network; and storing the deregistration of the first endpoint and the forwarding data in the (IMS) network.