Splittable traffic partition in WDM/SONET rings to minimize SONET ADMs
Theoretical Computer Science
A 10/7 + " Approximation for Minimizing the Number of ADMs in SONET Rings
BROADNETS '04 Proceedings of the First International Conference on Broadband Networks
The chord version for SONET ADMs minimization
Theoretical Computer Science
Better bounds for minimizing SONET ADMs
WAOA'04 Proceedings of the Second international conference on Approximation and Online Algorithms
Grooming of arbitrary traffic in SONET/WDM BLSRs
IEEE Journal on Selected Areas in Communications
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We consider an optical routing problem. SONET add-drop multiplexers (ADMs) are the dominant cost factor in SONET /WDM rings. The number of SONET ADMs required by a set of traffic streams is determined by the routing and wavelength assignment of the traffic streams. In this paper we consider the version where a traffic stream may be divided into several parts and assigned different wavelengths. A specific division may increase or decrease the number of ADMs needed for a given input. Following previous work, we consider two versions. In the arc version, the route of each traffic stream is given as input, and we need to decide on divisions of streams, and then to assign wavelengths so as to minimize the total number of used SONET ADMs. In the chord version, the route is not prespecified, but is assigned by the algorithm, and only after this step the divisions are done and wavelengths are assigned. The previously best known approximation algorithm for the arc version has a performance guarantee of $\frac{5}{4} = 1.25$ whereas the previously best known approximation algorithm for the chord version has a performance guarantee of $\frac{3}{2} = 1.5$. We improve both these results. We present a $\frac{36}{29} \approx 1.24138$-approximation algorithm for the arc version and a $\frac{7}{5} = 1.4$-approximation algorithm for the chord version.