Forward congestion notification indicates to upstream data switching devices that data is being transmitted through congested channels and some of the data or packets may be discarded. Backward congestion notification indicates to downstream devices that data is going through congested channels.
A signaling technique used by data transmission systems in order to indicate the status of network congestion. Devices that are communicating data across a network rely on congestion notification to determine when to send or delay the transmission of data packets.
