Protection of SONET based networks

The authors address the issue of telecommunications network protection, with particular reference to optical fibers and the new topologies made possible using the SONET signal format. It is found that the introduction of SONET-based networks provides an ideal opportunity to reappraise protection methodologies and to improve customer circuit availability significantly. The authors propose techniques for achieving these aims by examining a whole network from customer to customer so that weak links in the chain can be identified. In this manner, the network operator can be sure that investment in infrastructure is correctly targeted to provide a service that satisfies the customers´ expectations