Availability target redefinition for dynamic connections in WDM networks with shared path protection

Abstract

Recently, new solutions for automatized management in optical networks promise to allow customers to specify on-demand the terms of the Service Level Agreement (SLA) to be guaranteed by the Service Provider (SP). For a WDM mesh network that provides shared-path-protection we exploit the knowledge, among the other Service Level Specifications (SLS), of the connection holding time to dynamically manage the availability provided by the network to the connection during its lifetime. We monitor the actual availability provided to the connection, considering, e.g., the actual downtime experienced by the connection, and, every time the network status changes (typically, for a fault occurrence, or a connection departure or arrival), we evaluate the maximal availability that can be provided to the connection based on our knowledge of all the predictable network state changes, i.e., the future connection departures. Since some of the connection will be ahead of their stipulated availability (credit), while other connections will be behind their availability requirements (debit), we propose a mechanism that allows to “trade” availability “credits” and “debits”, by increasing or decreasing the shareability level of the backup capacity. So, we introduce an holding-time-aware approach which permits to manage in a more flexible manner the availability provided during the connection lifetimes. For a typical wavelength-convertible US nationwide network, our approach obtains significative savings on Blocking Probability (BP), while reducing the penalties due to SLA violations.