An Algorithm for Designing Rings for Survivable Fiber Networks

The introduction of SONET technology opens o p portunities for survivable network architectures, such as selfhealing rings, which can improve telecommunication reliability. This paper presents an algorithm for routing fiber around a ring in a network, when the network nodes, links, connectivity, and which offices are to be placed on that ring together are known. The algorithm aids automated survivable network planning. The algorithm was programmed in C, and run on a SPARCstation. Computation times on 47 examples of feasible and infeasible rings were reasonable. Overall, the average, minimum, and maximum runtimes were 0.41 sec., 0.06 sec., and 2.93 sec., respectively. Since the largest example network used in these results, 167 offices and 240 links, is the size of a typical large LATA network, the algorithm runs fast enough for the intended application. In most cases, the ring routing problem cannot be solved by traveling salesman algorithms. However, under certain conditions, the problem degenerates to the traveling salesman problem, and the ring routing algorithm degenerates to the nearest neighbor method of solving that problem.