Patent ID: 9451421
Filing Date: 2016-09-20
CPC Classification: H04L,H04M,H04W

Claim Text:
1. A method at a user equipment for registering with a third network node using an internet protocol (IP) multimedia subsystem (IMS), the method comprising: creating a tunnel between the user equipment and a first network node; authenticating a first public identity associated with the user equipment to the first network node; receiving configuration information from the first network node with a second private user identifier and a second public user identifier, the second private user identifier and second public user identifier being associated with a second network node; and registering with a third network node using the second private user identifier and the second public user identifier, wherein the first network node is a first mission critical push to talk (MCPTT) server, the second network node is a second MCPTT server, and the third network node is a serving call session control function (S-CSCF).