Cross-Layer Traffic Engineering in IP over WDM Networks

One approach for accommodating IP traffic on the wavelength division multiplexing (WDM) network is to construct a logical topology by establishing a set of lightpaths between nodes. The lightpath carries IP traffic and does not require any electronic packets processing at intermediate nodes, which reduces the load of packet processing at those nodes. However, if IP and WDM networks have their own routing functions, the lightpaths configured in the WDM network may not be fully utilized by IP unless the route of IP packets can be explicitly determined. Therefore, the integration of routing mechanisms is necessary to provide efficient resource utilization and flexible adaptation against traffic changes. In this thesis, we propose an integrated routing mechanism for IP over WDM networks. The key idea is to prepare a set of virtual-links based on the resource utilization of the WDM network, and then calculate the minimum cost route on the IP network. Our simulation results show that the throughput of our method is about 70 % higher than those of optimally designed logical topologies for a given traffic demand when traffic patterns change. We also develop a simulation method based on the fluid flow model, that is a flow-level simulation method, for simulating high-bandwidth and high-speed networks, such as IP over WDM networks. We verify the results of the flow-level simulation method by comparing with those of a conventional simulation method (packet-level simulation method). The flow-level simulation method consumes about 500 times less time than the packet-level simulation method.