Failure-aware idle protection capacity reuse

In modern communication networks different traffic classes require different quality of service (QoS) guarantees. It is therefore important for the benefit of both communication network users and network providers to meet each traffic class requirement while minimizing the utilized network resources. In this paper the failure-aware idle protection capacity reuse concept, FAIR for short, is presented and evaluated in a network scenario with two connection classes: high and low class lightpaths. High class lightpaths require full reliability against any single failure and are therefore shared path protected. Low class lightpaths might tolerate not be recovered after failure and are therefore unprotected. If low class lightpaths are disrupted by a link failure, they resort to best effort dynamic restoration. The FAIR concept is based on the utilization of idle (i.e., unutilized in the specific failure scenario) high class connection protection resources to recover disrupted low class connections. Numerical results show that the FAIR concept offers a simple yet efficient way to maximize network resource utilization while preserving connection reliability requirements without increasing control protocol overhead. The dynamic restoration of disrupted low class connections on free and idle resources brings a twofold advantage. On one hand it allows to significantly improve low class connection likelihood to be recovered. On the other hand, given a specific low class connection restoration blocking probability threshold, it increases the number of accepted low class connections during the provisioning phase. In addition the dependence of the aforementioned advantages on the network average nodal degree is negligible