Patent ID: 8873396

Claim:
A method of congestion marking in a data network using a protocol stack, the method comprising: receiving, at least one upstream network element having a higher layer in the protocol stack, lower layer congestion information communicated via the data network from at least one downstream network element having a lower layer in the protocol stack, the data network being external to the at least one upstream and the at least one downstream network element, the at least one downstream network element being operable to communicate via the data network with the at least one upstream network element using a flow of data traffic, the lower layer congestion information relating to data traffic congestion occurring at a downstream element in the flow at a lower layer in the protocol stack, the downstream element being within the lower layer; determining, at said at least one upstream network element, higher layer congestion information to be used in the higher layer, in dependence on the lower layer congestion information; and performing congestion marking by applying the higher layer congestion information to data traffic forwarded via the data network by an upstream network element in the higher layer.