Patent ID: 9107196
Filing Date: 2015-08-11
Classification: H04L,H04W

Abstract:
1. A method of operating a Session Initiation Protocol (SIP) system to control an Internet Protocol (IP) communication session between a first communication device and a second communication device, the method comprising: in a SIP control server, receiving a SIP bye message from the first communication device indicating a loss of the IP communication session with the second communication device, and in response, transferring a notification request for the second communication device to a SIP registration server, wherein the notification request requests a registration notification from the SIP registration server when the second communication device re-registers with the SIP registration server; in the SIP registration server, processing a SIP registration message from the second communication device, and in response to the notification request and the SIP registration message, transferring the registration notification to the SIP control server; and in the SIP control server, receiving the registration notification for the second communication device, and in response to the SIP bye message and the registration notification, transferring a SIP invite message to re-establish the IP communication session to the first communication device.