Patent ID: 8849266

Claim:
A method for ensuring continuity of management of communications sessions operated from a fourth-generation mobile terminal communicating on an IP network, said network including at least one radio network provided with a plurality of base stations with which said terminal is capable of communicating, said radio network being linked via access gateways to an interconnection network provided with communications session management application servers, said communication session management servers being SIP servers, the sessions of a mobile terminal being managed by one of said servers, said communications session management application servers including at least two IP addresses, a first address, identical for all servers, being used to access said servers from the mobile terminal, a second IP address being used to address the servers within the interconnection network, the method comprising: in the event of a movement of the mobile terminal resulting in a change of access gateway, transmitting an alert message to a new communications session management server, said alert message being transmitted by the new gateway in charge of the mobile terminal to the SIP server closest to said new gateway; said new server transmits an interrogation request destined for a multicast address to which said SIP servers are subscribed in order to recover the call context of the mobile terminal from the server which managed the sessions of said terminal prior to its movement; and the new session management server transmits an invitation message to the mobile terminal accompanied by connection parameters, in such a way that said terminal can connect to said new server, wherein said server including at least one mobility manager capable of recovering the call context of the mobile terminal from a different management server, wherein the mobile terminals communicate according to a “group call” call mode.