Online traffic engineering in GMPLS networks: From shortest-path to design-based routing

Shortest path algorithms such as SPF and CSPF axe widely used in online traffic engineering where connections need to be setup one at a time as connection requests arrive sequentially. We propose an approach, called design-based routing (DBR), whereby optimized paths computed offline are used to guide online path setups. DBR takes advantage of available demand information based on customer prescriptions, traffic projections and historical measurements, to build an approximate traffic demand matrix for path optimization. By means of simulation, we perform comparative evaluations under static and dynamic connections. The results indicate that DBR outperforms SPF and CSPF under a wide range of operating conditions and substantial uncertainty in traffic demand estimate.