Path computation element (PCE)-based traffic engineering in MPLS and GMPLS networks

This paper describes a new path computation model in Multi-protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. It introduces a path computation element (PCE), which is functionally separate from label switching routers (LSRs). The Path Computation Element (PCE) is an entity that is capable of computing a network path or route based on a network graph, and applying computational constraints. It is applied to intra-area, inter-area, inter-AS, and inter-layer traffic engineering. Then, we describes an PCE-based inter-layer traffic engineering framework. Inter-layer traffic engineering optimizes network resource utilization globally, i.e. taking into account all layers, rather than optimizing resource utilization at each layer independently. This allows better network efficiency to be achieved. We present two inter-layer path control models. One is a cooperation model with PCE and virtual network topology (VNT) manager. The other is higher-layer signaling trigger model. We compares these models in terms of functions of the network manager, node functions, and signaling time. We also discuss PCE standardizations in Internet Engineering Task Force (IETF).