Switch Placement Algorithms in Optical WDM Heterogeneous Networks
Date Issued
2005
Date
2005
Author(s)
Chang, Hsiao-Tse
DOI
en-US
Abstract
With the rapid development of Wavelength Division Multiplexing (WDM), a fiber can carry more and more wavelengths, but the complexity and the cost of Optical Cross-connects (OXCs) also increase. To deal with the problem, General Multi-Protocol Labeling Switching (GMPLS) defines three kind of switching methods: fiber switch capable, waveband switch capable, and lambda switch capable. In a heterogeneous optical network, we allow each node to have one of the switching capabilities. OXCs contribute most to the planning cost of optical networks, and the cost of OXCs is in proportion to the number of ports. Therefore, while a fiber can carry hundreds of wavelengths, the cost of OXCs increases proportionally. Furthermore, there is still a shortage of ports in the OXC design.
In this thesis, we allocate the switch nodes properly based on the lowest cost, and satisfy all the static traffic demand in a heterogeneous network. We model this problem as an integer programming problem with an objective function and several constraints, which is very complicated. Since the routing and wavelength assignment problem (RWA) is a well known NP-hard problem, and our problem contains the RWA problem, our problem is also NP-hard. As we cannot solve it in polynomial time by well known algorithms, we adopt Lagrangean relaxation as the solution approach.
In addition, we propose a simple heuristic algorithm modified from an RWA problem, and conduct several experiments on different network topologies. We find that the experiment results of Lagrangean Relaxation are better then those of the simple heuristic algorithm.
Subjects
光波長多工
光網路規劃
光纖交換
光波段交換
光波長交換
最佳化
拉格蘭日鬆弛法
數學規劃
Fiber Switch
Lagrangean Relaxation Method
Lambda Switch
Mathematical Programming
Network Planning
Optimization
Waveband Switch
WDM
Type
other
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