Explicit routing with QoS constraints in IP over WDM

Generalised multiprotocol label switching (GMPLS) is being developed as a unified control architecture for the optical transport network and the layers above it. GMPLS supports traffic engineering (TE) by allowing explicit routing (ER) of data-bearing paths across networks, which will help to guarantee quality of service (QoS) for types of services in IP over WDM networks. Although there have been many approaches to allocate resources in optical data networks using constrained linear programs, these do not consider the delays at layer 3, which impacts QoS. In networks where it is not possible to create a virtual topology at layer 3 that is a full mesh, more than one lightpath will be required to route traffic between certain pairs of source and destination IP routers. The authors present a technique for traffic engineering in optical networks that support QoS considering the traffic flows with delay QoS requirements across optical networks. This technique provides real-time services with a specific optical label switched path and optimises an objective function including the queueing delay at layer 3