Scalable multi-layer GMPLS networks based on hierarchical cloud-routers

The paper proposes the hierarchical cloud-router network (HCRN) to solve the problem of overcoming the scalability limit in a multi-layer generalized multi-protocol label switching (GMPLS) network. We define a group of nodes as a virtual node, called a cloud-router (CR). A CR consists of some number of nodes or lower-level CRs. A CR is modeled as a multiple switching capability (SC) node when it includes more than one kind of SC, such as fiber SC, lambda SC, time-division multiplexing (TDM) SC, packet SC, even if there are no actual multiple-SC nodes in the CR. The CR advertises its abstracted CR internal structure which is abstracted link state information inside the CR. A large-scale, multi-layer network can then achieve scalability by advertising the CR internal structure throughout the whole network. In this scheme, the ends of a link connecting two CRs are defined as interfaces of the CRs. We adopt the CR internal cost scheme between a CR´s interfaces to abstract the network. This CR internal cost is advertised outside the CRs via the interfaces. Our performance evaluation has shown that HCRN can operate a larger number of nodes than a normal GMPLS network. It can also bear more frequent network topology changes than a normal GMPLS network.