Patent ID: 8570853

Claim:
A Session Initiation Protocol (SIP) user agent for sharing a resource, comprising: a subscription engine associated with a first turret system and configured to subscribe to a second turret system to share a resource associated with the second turret system; a state change engine associated with the first turret system and configured to receive a state change notification corresponding to the resource, from the second turret system; and a failover engine configured to: upon detection of a mid-dialog Session Initiation Protocol (SIP) proxy failure, generate either a SIP RE-INVITE message or a SIP UPDATE message, the SIP RE-INVITE message or the SIP UPDATE message including routing information for a new communication path between the first turret system and the second turret system, and communicate either the SIP RE-INVITE message or the SIP UPDATE message to either the first turret system or the second turret system to invite the first turret system or the second turret system, respectively, to initiate a connection to the resource via the new communication path.