Optical Networking Best Practices Handbook

11.1. DESIGN FOR OPTICAL NETWORKS

Obviously, similar challenges as encountered in OPS were faced for optical circuit-switched approaches. Now, let us briefly examine recent work in the world of OPS [1].

In multistage switches, there is a tight coupling between the size of the central submatrices and the number of peripheral submatrices. One proposal is to "distribute" the functionality of the central matrices into the peripheral matrices. In this way all building blocks of a node are equal (SKOL—Stichting Katholiek Onderwijs Leiden—node), and adding one of these standard matrices can expand nodes. It alleviates the modularity problem of architectures: the size of the building blocks depends on the final (maximal) size of the switch to be implemented and thus encompasses initial overbuilding. By distributing the central stages of a classical architecture over SKOL input and output modules, even though overbuilding is still required, the cost of an initial (partial) matrix configuration is significantly reduced [1].

For circuit-switched approaches, various researchers start from ideas to exploit particular traffic characteristics to reduce the switch matrix sizes. Researchers can continue earlier work by others to reduce switch size for bidirectional traffic. A connection between A and B always implies a connection from B to A. Exploiting this bidirectionality allows significant cost cuts from traditional networks. Similar approaches have been proposed for designs of multicast switches ...