Fen Zhou, Miklos Molnar, Bernard Cousin, Chunming Qiao. Cost Bounds and Approximation Ratios of Multicast Light-trees in WDM Networks.. April 2011. Digital Object Identifier:
Résumé
The construction of light-trees is one of the principal subproblems for all-optical multicast routing (AOMR) in sparse splitting Wavelength Division Multiplexing (WDM) networks. Due to the light splitting constraint and the absence of wavelength converters, several light-trees may be required to establish a multicast session. However, the computation of the cost-optimal multicast light-trees is NP-hard. In this paper, first we study the cost bounds of the light-
trees built for a multicast session in unweighted WDM networks. Then, partially based on this result, the approximation ratios of some classical multicast light-tree computation algorithms, i.e., Reroute-to-Source (R2S) and Member-Only
(MO) algorithms are derived in both unweighted and non-equally weighted WDM networks. Moreover, integer linear
programming (ILP) formulations are introduced and carried out to search the optimal light-trees for multicast routing.
The cost bounds and approximation ratios of R2S and MO algorithms in some candidate WDM backbone networks are examined through simulations.