Supporting differentiated services in MPLS networks

Multi-protocol label switching is a relatively new technology based on the association of labels with routes and the use of labels to forward packets. In other words MPLS integrates the label-swapping paradigm with network-layer routing. Differentiated Services define a model for implementing scalable differentiation of QoS in the Internet. Packets are classified and marked, policed and shaped at the edge of the network in order to receive a particular per-hop forwarding behaviour on nodes along their path. The per-flow state does not need to be maintained in the interior network nodes, thus leading to increased scalability. This obviates the use of complex signalling protocols like RSVP. The inherent characteristics of MPLS make it a very good candidate for providing differentiated services. In this paper we describe various approaches which can be used to support differentiated services in MPLS environments.