Fiber network survivability

At the transport layer in interoffice and interexchange networks, shared protection rings (SPRINGS) interconnected at matched nodes can provide 100% restoration in milliseconds after cable cuts and central office failures. The author introduces the SPRING and explains how its capacity advantage over other ring configurations enables it to be the most economical solution in more applications. Transport restoration technologies-1+1 diversity, digital crossconnect systems, and SPRINGS-in interoffice and interexchange environments are compared. A representative network study is presented to justify the choice of SPRINGs and matched nodes for the target architecture. Recommendations on how to evolve today's asynchronous networks in preparation for a fully survivable SONET ring-based network are also provided. Generic ring planning guidelines and network examples are presented to demonstrate how today's networks can be evolved to provide end-to-end survivable SONET transport. An approach to ring-based network design that simplifies the planning process and minimizes network cost is provided.<<ETX>>