Routing of MPLS Flows over an Agile All-Photonic Star Network

In this paper, we study how MPLS flows are routed in an Internet that contains a centrally-controlled agile allphotonic star WDM network (AAPN). Two scenarios are considered, namely deploying AAPN within one OSPF (Open Shortest Path First) area and within several OSPF areas. Since the AAPN provides an NxN interconnection structure for the N edge nodes of the AAPN architecture, the straightforward usage of a routing protocol like OSPF leads to scalability problems. In the first scenario, we have identified several schemes by which this scalability problem can be reduced. The idea is to introduce "virtual routers" that represent a collection of edge nodes (and possibly also the core node), thus reducing the number of paths between the "routers". In the second scenario, we focus on inter-area routing in large-scale IP/MPLS networks. This paper proposes a novel framework for inter-area MPLS Traffic Engineering. The key to our proposal lies in deploying the AAPN architecture as the OSPF backbone area and introducing the concept of “virtual area border routers” (v-ABRs). Compared with other proposals, our proposal can provide globallyoptimized inter-area routing and has very good compatibility to existing traditional IP/MPLS routers.