PHOTO: an efficient shared-path-protection strategy based on connection-holding-time awareness

Recent trends in bandwidth markets show that customers are tending to ask providers for a large bandwidth but for a limited amount of time to support new short-term bandwidth-hungry applications. In order to meet these new requirements, progress in network technologies (fast and reconfigurable switching equipment) and protocols [such as generalized multiprotocol label switching (GMPLS) and automatically switched optical network (ASON)] is paving the road towards flexible optical transport networks in which leasable circuits could be set up and released on a short-term basis. As a result, for dynamic traffic, the holding time of connection requests can be known in advance. The authors propose to exploit knowledge of connection holding time to design an efficient algorithm, called PHOTO, for the dynamic provisioning of shared-path-protected connections in optical mesh networks. The core idea of the proposal consists of exploiting the knowledge of the holding time of connection requests to minimize resource overbuild (RO) due to backup capacity and hence achieve resource-usage efficiency. For a typical US nationwide network, savings on RO of up to 10% were obtained for practical scenarios compared to a holding-time-unaware, but otherwise shared-path-efficient, approach.