Optical Networking Best Practices Handbook

1.2. DISTRIBUTED IP ROUTING

The idea behind the distributed IP router is to minimize routing operations in a large optical network. In the distributed IP router, the workload is shared among nodes and the routing is done only once.

Thus, the optical network model considered in this section consists of multiple optical crossconnects (OXCs) interconnected by optical links and nodes in a general topology (referred to as an optical mesh network). Each OXC is assumed to be capable of switching a data stream from a given input port to a given output port. This switching function is controlled by appropriately configuring a crossconnect table. Conceptually, the crossconnect table consists of entries of the form <input port i, output port j>, indicating that the data stream entering input port "i" will be switched to output port "j." A lightpath from an ingress port in an OXC to an egress port in a remote OXC is established by setting up suitable crossconnects in the ingress, the egress, and a set of intermediate OXCs such that a continuous physical path exists from the ingress to the egress port. Lightpaths are assumed to be bidirectional; the return path from the egress port to the ingress port follows the same path as the forward path. It is assumed that one or more control channels exist between neighboring OXCs for signaling purposes.

1.2.1. Models: Interaction Between Optical Components and IP

In a hybrid network, some proposed models for interaction between IP and optical components ...