Dynamic provisioning of shared-backup path protected connections with guaranteed availability requirements

In optical networks, shared-backup path protection (SBPP) can optimize network resources utilization in scenarios where connection resilience requirements are not achieved without protection, but are exceeded with dedicated-path protection (DPP). However, savings in capacity allowed by backup capacity sharing are achieved at the cost of connection availability degradation. This paper presents a strategy for provisioning connections with guaranteed availability in a dynamic traffic scenario that attempts to minimize the allocation of spare capacity. Connections can be unprotected or protected by SBPP - which in some cases degenerate to DPP - depending on the connection availability requirements. This provisioning strategy employs the previously published matrix-based approach for connection unavailability estimation in SBPP protected networks which offers accurate results for networks of national size. We investigate the performance, in terms of blocking and resource sharing, of three availability classes (availability of 0.999, 0.9999 and 0.99999) that coexist in two representative network topologies without wavelength conversion. The results indicate that SBPP is a viable option for networks of national dimensions, but the backup sharing of high availability connections is strongly limited in networks of continental dimensions