Patent ID: 8457138

Claim:
A communication system for propagating a congestion notification of a frame relay network through a packet network, comprising: a first interworking function (IWF); and a second IWF, the second IWF configured to receive a first frame from a first frame relay node of the frame relay network, the first frame having payload data and a header, the header comprising a frame relay congestion notification transmitted from a source node for reception by a destination node, the second IWF configured to de-encapsulate the payload data from the first frame, and to encapsulate the payload data, thereby forming a data packet compatible for transmission via the packet network, the second IWF further configured to transmit continuity check messages (CCMs) and the data packet via the packet network to the first IWF and to control at least one of the CCMs such that the frame relay congestion notification is propagated from the second IWF to the first IWF via the CCMs, wherein the frame relay congestion notification defines: (1) a Forward Explicit Congestion Notification (FECN) value indicating that the destination node is to send requests for additional frames to the source node more slowly or (2) a Backward Explicit Congestion Notification (BECN) value indicating that the destination node is to send data to the source node more slowly, wherein the data packet is not indicative of the frame relay congestion notification, wherein the second IWF is configured to de-encapsulate the data packet, thereby recovering the payload data, wherein the first IWF is configured to encapsulate the payload data from the data packet, thereby forming a second frame, and to transmit the second frame to a second frame relay node of the frame relay network, wherein the first IWF is configured to include the frame relay congestion notification in a header of the second frame based on the CCMs.