Constraint-Based Hybrid Resiliency Mechanisms for Better Resource Utilization and Service Performance Quality in ASON SLA

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In optical transport networks, contents of service level agreement (SLA) are not standardized yet. There is a general recommendation to include network resiliency mechanisms in SLA contracts by considering trade-off between resource utilization and service performance quality. This research work proposes two solutions to fulfil these trade-off requirements in network resiliency mechanisms. The first solution is employing a Routing and Wavelength Assignment (RWA) algorithm that can utilize network resources efficiently in Automatically Switched Optical Network (ASON) service provisioning. The research work conducts blocking probability and network availability comparison simulations for Shared Risk Group (SRG)-Disjoint Aware First-Fit Routing, Alternate Routing, Least Congested Routing and Load Sharing routing algorithms coordinated with First-Fit wavelength assignment algorithm in 1+1 Dedicated Path Protection (DPP) and Restoration schemes. The simulations performed on Net2Plan tool show that Alternate Routing algorithm has best overall results in blocking probability and network availability for both protection and restoration. The second solution is enhancing service performance qualities by combining protection and restoration. This research work proposes new constraint-based hybrid resiliency mechanisms (1+1 Link-Disjoint + Restoration, 1+1 Node-Disjoint + Restoration and 1+1 SRG-Disjoint + Restoration). The performance of these hybrid resiliency mechanisms is evaluated using Net2plan simulation tool. The results show that the network availability and recoverability performances are improved when it is compared to non-combined counter parts. 1+1 Node-Disjoint + Restoration shows best recoverability at lower traffic loads during link or SRG failures. At higher traffic loads, 1+1 SRG-Disjoint + Restoration performs best in recoverability during SRG failures. For instance, 1+1 SRG-Disjoint + Restoration has on average 16.8% higher recoverability than 1+1 Link-Disjoint + Restoration, at higher traffic loads. These performance enhancements are obtained with cost of relatively higher blocking probability.



Alternate Routing, ASON, Availability, blocking probability, DPP, First-Fit, GMPLS, Hybrid Resiliency, Link-Disjoint, Load Sharing, Network Resiliency, NodeDisjoint