Minimizing Maximum Logical Link Congestion in Packet Switched Optical Networks

We consider the problem of designing logical optical network topology for a given physical topology (or fiber layout) and a given traffic demand matrix between the end-users. Traffic between the end-users is carried in a packet-switched form and the objective of our logical topology design is to minimize the maximum congestion on the logical links in the logical topology. The logical links are realized by wavelength continuous paths or lightpaths between end-users and they are routed via wavelength-selective routers. Note that a topology with lower maximum link congestion will allow its traffic demand matrix to be scaled up by a larger factor. In the logical topology, each node is equipped with a limited number of optical transceivers, hence logical connections cannot be setup between every pair of nodes. In this paper we present an analytical model for obtaining the maximum and average logical link loads for a given logical network and traffic demand matrix. The model is confirmed via simulation. A heuristic algorithm for constructing a logical topology that reduces maximum logical link congestion is also presented.