US Patent 10009277 Backward congestion notification in layer-3 networks

Communication apparatus includes a plurality of interfaces configured to be connected to a Layer-3 packet network and to serve as ingress and egress interfaces to receive and transmit packets from and to the network. Routing logic is coupled to process respective Layer-3 headers of the packets received through the ingress interfaces and to route the packets via the egress interfaces to respective destinations indicated by the Layer-3 headers. Congestion detection logic is coupled to identify a flow of the received packets that is causing congestion in the network and a Layer-3 address from which the flow originates, and to direct the routing logic to route a backward congestion notification message (CNM) packet via one of the egress interfaces to the identified Layer-3 address.