Conference Paper

Multicast routing and wavelength assignment in WDM networks with limited drop-offs

Inst. of Appl. Math., Chinese Acad. of Sci., Beijing, China
DOI: 10.1109/INFCOM.2004.1354520 Conference: INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies, Volume: 1
Source: DBLP

ABSTRACT In WDM networks with limited drop-offs, the route of a multicast connection consists of a set of light-trees. Each of the light-tree is rooted at the source node and contains no more than a limited number, say k, destination nodes due to the power loss of dropping optical signals off at destination nodes. We call such a light-tree k-drop light-tree. In this paper we study the multicast routing problem of constructing a set of k-drop light-trees that have the minimal network cost. The network cost of a set of light-trees is defined as the summation of the link cost of all the light-trees. We first prove that this problem is polynomial-time solvable for k=2 and NP-hard for k≥3. We then propose a 4-approximation algorithm for the problem for k ≥3. A wavelength assignment algorithm is also proposed to assign wavelengths to the light-trees of a multicast connection. In the end we give simulation results showing that k-drop multitree muting can significantly save not only the network cost but also wavelengths used. Moreover, when k≥5 its performance is very close to the case where k is infinite (i.e., the case of using a single tree for a multicast connection).

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    • "The RoMR protocol (Robust Multicast Routing protocol) in [14] builds multiple reliable multicast trees that adapt to topology changes in a dynamic fashion. Studies in [15] [16] use multiple subtrees, each spanning the source node and some destination nodes to solve wavelength assignment in WDM networks. Different from the above schemes, our scheme simultaneously uses the multiple paths or trees, so that the aggregate bandwidth of them can meet the bandwidth requirement of a single QoS request when reaching a suboptimal goal of minimizing the network cost under the delay bound. "
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    • "where multicast sessions are dynamically set up and released over time, was also shown to be solvable in linear time if the number of wavelengths per link, transmitters and receivers per node, and switch degree are constants. In [19] and [14], the authors explore multicast routing under the multi-tree model. "
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