Principles and technologies for planning survivability-a metropolitan case study

The principles and technologies which Bell Canada is evaluating to make its metropolitan networks survivable against cable cuts and central office failures are presented. A number of restoration technology alternatives are examined through detailed application studies of the Montreal network. The results presented show the impact of technology enhancements and the emerging SONET standards on the restoration choice. Economic and operational considerations led to the preference of 1+1 diverse routing and ring architectures for metropolitan survivability. Results of an access link survivability assessment showed that, with some reconfiguration to fiber already in place, the access network could be made survivable in the downtown core