Routing of 40 Gb/s traffic in heterogeneous optical networks

In this paper, we introduce the routing of multi-rate traffic (RMT) problem that arises in current backbone networks required to carry the new 40 Gb/s traffic streams. The RMT problem is informally defined as the process of finding the best routing which maximizes the total bandwidth carried in the network, for a set of sessions, within a given TDM equipment budget. We propose a two-phase iterative optimization scheme (two-phase RMT). This scheme first obtains a basis solution used in routing 40 Gb/s traffic only on OC-768 capable links without the use of TDM equipment. In the second phase, an iterative routing, re-routing and resource allocation step is used to optimize the total bandwidth carried in the network while allowing 40 Gb/s traffic to be routed on OC-768 incapable links by the proper installation of TDM multiplexors and demultiplexers at some strategic locations in the network. Numerical results demonstrate the performance of the proposed approach on a mesh-type heterogeneous topology.