Comparison of Mesh Protection and Restoration Schemes and the Dependency on Graph Connectivity

We present a series of experimental designs based on different mesh survivability principles and study how the working and spare capacity requirements of each network type vary with the network average nodal degree or notionally, the connectivity of the facilities graph of the network. This is accompanied by an attempt at some simple theories for bounding or estimating how capacity and redundancy will depend on network average nodal degree. Six types of restorable mesh network designs are compared: 1+1 non-shared backup path protection, span restoration with and without joint optimization of working and spare paths, chain-optimized span restoration, shared backup path protection, and true dynamic path restoration. It is thought that this may be the first comprehensive comparative study of restorable mesh network capacity requirements viewed across a range of network degree as opposed to point comparisons of capacity on single study networks. By showing how each scheme responds to the degree of connectivity of the facilities graph the work also provides new insights about facilities graph topology evolution.