US Patent No. 10,193,938

OPERATING A NETWORK NODE


Patent No. 10,193,938
Issue Date January 29, 2019
Title Operating A Network Node
Inventorship Salem Al-Damluji, Enfield (GB)
Phillip James Springett, Enfield (GB)
Assignee Metaswitch Networks Ltd., Enfield (GB)

Claim of US Patent No. 10,193,938

1. A method of operating a network node, the method comprising, at the network node, during setup of a communication session between a calling party and at least a called party:receiving a communication session setup request message from a calling party device associated with the calling party;
forwarding the received communication session setup request message to a forking proxy responsible for providing communication session forking services in relation to at least the called party;
receiving a first provisional response message from a first device, the first provisional response message comprising first session description protocol (SDP) data, wherein the first provisional response message is received from the first device in response to the forwarding of the received communication session setup request message to the forking proxy;
forwarding the first provisional response message on to the calling party device, the forwarded first provisional response message comprising at least a part of the first SDP data;
receiving a first provisional acknowledgement message from the calling party device and receiving a second provisional acknowledgement message from the first device, thereby enabling media data sent during setup of the communication session before the communication session is established to flow between the first device and the calling party device;
receiving a second provisional response message from a second device, the second provisional response message comprising second SDP data, wherein the second provisional response message is received from the second device in response to the forwarding of the received communication session setup request message to the forking proxy;
receiving an answer message which accepts the communication session setup request received in the communication session setup request message from the calling party device; and
forwarding the answer message to the calling party device, wherein the method further comprises:
in response to receipt of the second provisional response message, transmitting, during setup of the communication session, a first message to the calling party device, which offers to update the SDP data to at least a part of the second SDP data, before the answer message is transmitted to the calling party device;
receiving a second message from the calling party device which accepts the offer to update the SDP data to the at least part of the second SDP data;
responsive to receipt of the second message, removing the second SDP data from the second provisional response message, and
transmitting the second provisional response message from which the second SDP data has been removed to the calling party device; and
receiving a third provisional acknowledgement message from the calling party device and receiving a fourth provisional acknowledgement message from the second device, thereby enabling media data sent during setup of the communication session before the communication session is established to flow between the second device and the calling party device.