Routing and Protection in GMPLS Networks: From Shortest Paths to Optimized Designs

Shortest path algorithms such as SPF and CSPF are widely used in online traffic engineering where connections need to be set up 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. Offline path computation in GMPLS networks does not pose a significant challenge since optical core or metro networks typically consist of a few dozen to 100s of nodes compared to 100s to 1000+ nodes in pure data networks. 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.