Supporting differentiated services with per-class traffic engineering in MPLS

Differentiated services (DiffServ) and MPLS are two major building blocks for providing multi-class services over IP networks. The performance and efficiency of DiffServ architecture can be enhanced with per-class traffic engineering. We propose a new multi-protocol label switching (MPLS) traffic engineering scheme. Based on a constraint-based routing modified from our previously proposed QoS routing algorithm, it enhances the original E-LSP with per-class traffic engineering and load balancing. Major components of the scheme including labeling, load balancing, and routing are described; its features are carefully analyzed against desired traffic engineering requirements. With detailed simulation, we evaluate and compare the proposed scheme with two other schemes: the original E-LSP and E-LSP with load balancing, for their support of expedited forwarding (EF), assured forwarding (AF), and best effort (BE) service classes. We found that, through better utilization of network resources, the proposed scheme is able to accommodate more QoS flows with desired requirements; at the same time it offers better delay and delay jitter for existing EF and AF classes, and improves the overall performance of BE class. We believe that the proposed scheme is an important step for providing scalable, multi-service solution in future IP networks.