Packet forwarding apparatus has an input for receiving packets; a packet classifier arranged in operation to read a class indication in received packets and in dependence thereon to pass packets to a class-based policer associated with the class indicated; a plurality of class-based policers, each operable to assign a provisional indication to packets of the associated class in response to a measure of the load presented by packets of the class exceeding a predetermined class-based threshold; a multi-class policer operable to receive provisionally-indicated packets processed by the class-based policers, and to assign a congestion indication to packets having the provisional indication in response to congestion arising at the packet forwarding apparatus; and an output for presenting packets processed by the multi-class policer for onward transmission from the apparatus.