Flow aggregated, traffic driven label mapping in label-switching networks

Label-switching technology enables high performance and flexible layer-3 pa cket forwarding based on the fixed-length label information that is mapped to the layer-3 packet stream. A label-switching router (LSR) forwards layer -3 packets based on their layer-3 address information or their label inform ation that is mapped to the layer-3 address information. Two label-mapping policies have been proposed. One is traffic-driven mapping, where the label is mapped for a layer-3 packet stream of each host-pair according to the a ctual packet arrival. The other is topology-driven mapping, where the label is mapped in advance for a layer-3 packet stream toward the same destinati on network, regardless of actual packet arrival to the LSR, This paper eval uates the required number of labels under each of these two label-mapping p olicies using real backbone traffic traces, The evaluation shows that both label-mapping policies require a large number of labels. In order to reduce the required number of labels, we propose a label-mapping policy that is a combination of the two label-mapping policies above. This is traffic-drive n label mapping for the packet stream toward the same destination network. The evaluation shows that the proposed label-mapping policy requires only a bout one-tenth as many labels as the traffic-driven label mapping for the h ost-pair packet stream and the topology-driven label mapping for the destin ation-network packet stream.