A communication system for propagating a congestion notification of a frame relay network through a packet network has a first interworking function (IWF). In addition, the system has a second IWF, the second IWF receives a first frame from a first frame relay node, the first frame having payload data and a header, the header comprising a frame relay congestion notification. The second IWF de-encapsulates the payload data from the first frame and encapsulates the payload data thereby forming a data packet compatible for transmission via the packet network. In addition, the second IWF transmits continuity check messages (CCMs) and the data packet via the packet network to the first IWF and controls at least one of the CCMs such that the frame relay congestion notification is propagated to the first IWF.