The problem of dynamic multicast routing and wavelength assignment (MC-RWA) in the wavelength-routed wavelength-division-multiplexing networks is addressed. Current solutions to this problem always rely on homogeneous network constructions. However, future backbone networks tend to be heterogeneous in nature. Thus, the dynamic MC-RWA problem should be studied in a more realistic situation by considering the heterogeneity of network structures. A new graph model is proposed for the MC-RWA problem. This model is based on layered auxiliary graph which is generic and able to support various node architectures and heterogeneous network structures. Based on this graph model, the dynamic MC-RWA problem can be simply solved by an efficient multicast tree algorithm on various light-splitting and wavelength-conversion scenarios. In general, this graph model provides a universal platform to study different aspects of the dynamic MC-RWA as well as related problems.

The multicast wavelength assignment problem in wavelength-routed wavelength-division multiplexing networks with limited wavelength conversions is addressed. A new multi-wavelength multicast wavelength assignment (MMWA) algorithm has been developed based on the multi-wavelength assignment strategy, by allowing multiple available wavelengths in a link to carry the multicast signal. This new multicast wavelength algorithm provides advantages for the network with limited wavelength conversions, by accommodating more multicast requests and providing good trade-off between wavelength cost and wavelength conversion cost. Simulation results show that the MMWA algorithm can satisfy more multicast requests in comparison with the previous single-wavelength assignment strategy. The improvement can be as high as 50–80%. This is highly significant. The MMWA algorithm also provides a good cost trade-off by making significant reduction of wavelength conversion cost (over 50%) while keeping the additional wavelength usage within a reasonable range (around 15%).

This paper addresses the multicast wavelength assignment (MC-WA) problem in wavelength-routed WDM networks with full light splitting and wavelength conversion capabilities. Current approaches are based on the multicast switch model that supports only split-convert (S-C) switch scheme. This scheme leads to redundant wavelength conversions for a given multicast request. In this paper, we propose a new split-convert-split (S-C-S) switch scheme capable of eliminating the redundant wavelength conversions. In order to implement this new switch scheme, we develop a new multicast switch model based on the concept of sharing of light splitters and wavelength converters. Furthermore, existing multicast wavelength assignment algorithm allows only one wavelength to carry the light signal on a fiber link, the so-called single-wavelength assignment strategy. In this paper, we explore the advantages of a new multi-wavelength assignment strategy which allows multiple available wavelengths in a link to carry the multicast signal. This will reduce the number of wavelength conversions required for the multicast request. Consequently, based on the new S-C-S multicast switch model and the new multi-wavelength assignment strategy, we generalize the existing algorithms to produce a new Multicast 'Wavelength Assignment Algorithm (MWAA) to support both the new switch model and the new wavelength assignment strategy. Compared with the existing algorithm, our new algorithm is a more general one which makes the multicast wavelength assignment more flexible, covering different switch schemes and different assignment strategies. In addition, it delivers good performance in term of minimizing the number of wavelength conversions. The improvement percentage is sensitive to the maximum out-degree value of a node, D. For a 100-node multicast tree, the improvement percentage increases from 38% at D = 3 to about 73% at D = 16. This is highly significant.

This paper addresses the multicast wavelength assignment problem in wavelength-routed WDM networks with full light splitting and wavelength conversion capabilities. Current approach is based on the assumption that only one available wavelength can be used in a link. This assumption is rather restrictive. In this paper, we liberalize the assumption by allowing multiple available wavelengths in a link to carry the multicast signal. Consequently, based on a multicast-capable switch model, we develop a new multiwavelength multicast wavelength assignment (MMWA) algorithm to carry the multicast signal. Simulation results show that our new algorithm outperforms the existing MNWC algorithm by making significant reduction of wavelength conversion cost. The improvement percentage of MMWA is sensitive to the maximum out-degree value of a node, D. For L=10 (L being the maximum number of available wavelengths on each link), the improvement percentage increases from 20% at D=4 to about 70% at D=16. This is a significant improvement.