Routing Problem In WDM Networks Research Articles

Delay-constrained survivable multicast routing problem in WDM networks with shared segment-based protection

For a delay-constrained multicast transmission request, the goal of delay-constrained survivable multicast routing problem is to provide the primary multicast tree and the tree protecting sparse resources. The shared segment-based protection (SSBP) method is used in this article to protect the delay-constrained multicast transmission. Two heuristic methods are proposed to find the delay-constrained primary tree and the backup segments with delay constraint. Experiments are conducted to evaluate the performance of the proposed methods, and the performance to be evaluated includes wavelength efficiency ratio (WER), blocking ratio (BR), and executing time. Simulations show that the SSBP method can get better BR and WER than the previous results demonstrated Din and Jiang (Comput Commun 35(10):1172---1184, 2012).

Delay-constrained survivable multicast routing problem in WDM networks

In WDM network, link failure may cause service disruption and may lead to lose significant information. Especially, for a multicast transmission when link on a light-tree that carries traffic to multiple destinations failed, the traffic to all the downstream destinations along the failed link will be affected. For a given multicast request with a maximum delay denoted as Δ, the delay-constrained survivable multicast mechanism provides the primary multicast tree and some sparse resources to protect it. When link failure occurred, the multicast transmission is recovered by using sparse resources while ensuring that the backup tree can satisfy the delay constraint. This problem is called Delay-Constrained Survivable Multicast Routing Problem (DCSMRP). In this article, three protection methods are used to solve this problem; they are: Delay Constrained Link-disjoint Tree Protection (DCLTP), Delay Constrained Disjoint-Paths Protection (DCDPP) and Delay Constrained Span p-Cycle Protection (DCSP). Three multicast routing methods are proposed for the respective protecting methods to find the primary multicast tree and backup resources with delay constraint. Experiments are conducted to evaluate the resource utility ratio (RUR), blocking ratio (BR) and executing time (RT) of these methods. Simulations show that the DCSP method can get best BR for the cases with greater delay bound (for the cases with delay bound Δ>5.5ms.) The RUR of DCSP is worse than that of DCLTP and DCDPP (in the cases with delay bound Δ⩾7.5msec), and the computational time of the DCDPP is faster than that of the DCSP and DCLTP.

A multi-granularity evolution based Quantum Genetic Algorithm for QoS multicast routing problem in WDM networks

QoS multicast routing problem in WDM networks is investigated, and an improved algorithm Multi-granularity Evolution based Quantum Genetic Algorithm (MEQGA) is proposed to address it. Based on Quantum Genetic Algorithm (QGA) with quantum rotation gate strategy, MEQGA introduces multi-granularity evolution mechanism, which allows different chromosomes of one generation to have different rotation angle step values to update. In term of this mechanism, MEQGA can significantly improve its capability of exploration and exploitation, since its optimization performance does not over-depend on the single rotation angle step scheme shared by all chromosomes any longer. MEQGA also presents an adaptive quantum mutation operation which is able to avoid local search efficiently. A repair method is applied to eliminate illegal graphs as many as possible hence more excellent solutions will appear in each evolutionary generation. Simulation results show that, for the QoS multicast routing problem, MEQGA outperforms other heuristic algorithms and is characterized by robustness, high success ratio, fast convergence and excellent capability on global searching.