An improved distributed routing protocol for multi-domain optical networks using topology aggregation

Multi-domain networks consist of several domains connected together by inter-domain physical links. Routing and failure protection in such networks are complex issues that have only started to receive attention. One source of difficulties lies in the lack of shared information among domains, such as network topologies, bandwidth, and size of the network. This kind of information can only be estimated across the different domains. Truong and Jaumard in "Using Topology Aggregation for Efficient Shared Segment Protection Solutions in Multi-Domain Networks", IEEE journal, propose a two-step routing and protection approach where in the first step a topology aggregation and cost estimation is obtained to model the inter-domain network followed by a detailed intra-domain routing step. Different approximation techniques are used to estimate costs and residual bandwidths in the aggregated model of the multi-domain network. But protection and routing interact in a complex manner, which renders difficulty in these estimations. In this thesis, we propose a technique that aims at improving the cost estimation in the aggregated topology.;The virtual estimated cost can be improved by computing “real virtual edges” whenever there is an inter-domain request in multi-domain network. The estimated cost is significantly improved by the proposed method in this study though there is some overhead involved. The complete protocol is simulated using Boost Graph Library in C++ environment. The simulation was performed on a large graph and results were compared with original GROS heuristic. From the tests, we can confirm that the heuristic proposed in this thesis will help to achieve better cost estimation.