Patent ID: 7391765

Claim:
A congestion control system for a VoIP network comprising: first and second VoIP gateways to generate at least one packet flow on the IP network, wherein the at least one packet flow is generated between the first VoIP gateway and the second VoIP gateway to establish a telephonic communication call between users; a relay router including to a plurality of queues, storing packets of packet flows, each of which passes through the relay router and has a priority, in one of the plurality of queues corresponding the priority and forwarding packets stored in the plurality of queues according to the priority, when a new packet flow that passes through the relay router and has a predetermined priority is generated between the first and second VoIP gateways, the relay router judging whether the new packet flow causes congestion in the relay router, if it is judged that the new packet flow causes the congestion, the relay router transmitting a congestion notice relating to the new packet flow; and a control device for the first and second VoIP gateways to receive the congestion notice from the relay router or the relay router via any one of the first and second VoIP gateways and to execute congestion control with respect to the new packet flow to avoid storing packets of the new packet flow in one of the plurality of queues corresponding to the predetermined priority in the relay router when a reception frequency of the congestion notice reaches a predetermined value.