US 12,149,566 B1
Call Session Control Function (CSCF) reselection in wireless communication networks
Harikishore Allu Balan, Lynnwood, WA (US); and Saqib Badar, Bellevue, WA (US)
Assigned to T-MOBILE INNOVATIONS LLC, Overland Park, KS (US)
Filed by T-MOBILE INNOVATIONS LLC, Overland Park, KS (US)
Filed on Jul. 5, 2023, as Appl. No. 18/346,986.
Int. Cl. H04L 65/1045 (2022.01); H04L 65/1016 (2022.01); H04L 65/1069 (2022.01); H04L 65/1104 (2022.01)
CPC H04L 65/1045 (2022.05) [H04L 65/1016 (2013.01); H04L 65/1069 (2013.01); H04L 65/1104 (2022.05)] 20 Claims
OG exemplary drawing
 
1. A method of operating a wireless communication network to perform route advance for Internet Protocol Multimedia Subsystem (IMS) voice calls, the method comprising:
Call Session Control Function (CSCF) circuitry receiving a Mobile Originating Session Initiation Protocol (MO SIP) invite message sent from an originating User Equipment (UE) for a voice call to a terminating UE;
the CSCF circuitry transferring a request to E.164 Number Mapping (ENUM) circuitry to route the MO SIP invite;
the ENUM circuitry receiving the request, determining routing information for the MO SIP invite, determining a realm type for the terminating UE, and indicating the routing information and the realm type to the CSCF circuitry; and
the CSCF circuitry receiving the routing information and the realm type, transferring the MO SIP invite based on the routing information, and storing the realm type in association with the MO SIP invite.