Differentiated survivability with improved fairness in IP/MPLS-over-WDM optical networks
This paper addresses the priority-fairness problem inherent in provisioning differentiated survivability services for sub-lambda connections associated with different protection-classes in IP/MPLS-over-WDM networks. The priority-fairness problem arises because, high-priority connections requiring high quality of protection such as lambda level preconfigured lightpath protection are more likely to be rejected when compared to low-priority connections which may not need such a high quality of protection. A challenging task in addressing this problem is that, while improving the acceptance rate of high-priority connections, low-priority connections should not be over-penalized. We propose two solution-approaches to address this problem. In the first approach, a new inter-class backup resource sharing (ICBS) technique and a differentiated routing scheme (DiffRoute) are adopted. The ICBS is investigated in two methods: partial- and full-ICBS (p-ICBS and f-ICBS) methods. The DiffRoute scheme uses different routing criteria for the traffic classes. In the second approach. two rerouting schemes are developed. The rerouting schemes are applied with the DiffRoute and ICBS. The rerouting schemes employ inter-layer backup resource sharing and inter-layer primary-backup multiplexing for the benefit of high-priority connections, thus improving fairness. Our findings are as follows. (1) The application of p-ICBS and DiffRoute yields improved performance for high-priority connections. However, it shows penalized performance for low-priority connections. On the other hand, the collective application of f-ICBS and DiffRoute yields significantly improved performance for high-priority connections with no penalized performance as the performance of low-priority connections is also improved. (2) The rerouting schemes, when applied with the DiffRoute and ICBS methods, further improve the performance of high-priority traffic without significantly affecting the performance of other traffic. (C) 2008 Elsevier B.V. All rights reserved.
survivability fairness optical networks rerouting wavelength division multiplexing