Patent ID: 9197674
Filing Date: 2015-11-24
Classification: H04L

Abstract:
1. A user agent device comprising: a processor and a memory configured to store instructions for execution by the processor, the processor configured to execute the stored instructions for: retrieving presence/IM information associated with the user agent device from SIP/SIMPLE devices located within a home network while the user agent device is located in the home network, wherein the retrieving is initiated by a trigger event where the user agent is relocating from the home network to a visited network; obtaining a new IP address from the visited network when the user agent device is relocated from the home network to the visited network; sending the new IP address in a single SIP REGISTER request to a first SIP registrar located within the home network, the single SIP REGISTER request containing a single CONTACT field that contains both the new IP address from the visited network and instructions to delete an old IP address; and partially registering the user agent device with a second SIP registrar located within the visited network using by sending a SIP REGISTER request to the second SIP registrar in the visited network containing the single CONTACT field that contains both the new IP address and a BODY field that contains authorization/authentication information which was retrieved from the user agent when carried by the user agent from the home network to the visited network.