Availability Analysis and Enhanced Availability Design in p-Cycle-Based Networks

摘要

p-Cycle protection is a fairly new survivability scheme that has the interesting properties of offering restoration speeds essentially the same as those offered by ring protection while requiring almost as little redundant capacity as adaptive mesh restoration [D. Stamatelakis, W.D. Grover, IEEE Transactions on Communications, vol. 48, no. 8, (August 2000), pp. 1262-1265]. This paper presents the first analytical consideration of the availability of paths in a network protected by p-cycles. Results confirm the importance that cycle sizes play in terms of availability and suggests principles or strategies for achieving high availability of paths in a network protected by p-cycles. Based on these insights, two new formulations for joint service path provisioning and capacity planning are proposed. The first one offers a way to improve the availability of selected service paths by using a different routing strategy for them than for regular service paths. The second formulation enables a new class of service paths that are offered two protection options instead of just one. That class of service paths is expected to see its availability improved in a quantum step way relative to the availability of paths having only one protection option.