TY - JOUR

T1 - Wavelength converter placement under different RWA algorithms in wavelength-routed all-optical networks

AU - Chu, Xiaowen

AU - Li, Bo

AU - Chlamtac, Imrich

N1 - Funding Information:
Paper approved by W. C. Kwong, the Editor for Optical Communications of the IEEE Communications Society. Manuscript received November 6, 2001; revised June 7, 2002; August 24, 2002; October 15, 2002. This work was supported in part by Research Grants Council (RGC) grants under Contract AoE/E-01/99, Contract HKUST 6163/00E, and Contract HKUST 6195/02E. This paper was presented in part at the SPIE Optical Networking and Communications Conference (OptiComm) 2002, Boston, MA, July 29-August 2, 2002.

PY - 2003/4

Y1 - 2003/4

N2 - Sparse wavelength conversion and appropriate routing and wavelength assignment (RWA) algorithms are the two key factors in improving the blocking performance in wavelength-routed all-optical networks. It has been shown that the optimal placement of a limited number of wavelength converters in an arbitrary mesh network is an NP-complete problem. There have been various heuristic algorithms proposed in the literature, in which most of them assume that a static routing and random-wavelength assignment RWA algorithm is employed. However, the existing work shows that fixed-alternate routing and dynamic routing RWA algorithms can achieve much better blocking performance. Our study further demonstrates that the wavelength converter placement and RWA algorithms are closely related in the sense that a well-designed wavelength converter placement mechanism for a particular RWA algorithm might not work well with a different RWA algorithm. Therefore, the wavelength converter placement and the RWA have to be considered jointly. The objective of this paper is to investigate the wavelength converter placement problem under the fixed-alternate routing (FAR) algorithm and least-loaded routing (LLR) algorithm. Under the FAR algorithm, we propose a heuristic algorithm called minimum blocking probability first for wavelength converter placement. Under the LLR algorithm, we propose another heuristic algorithm called weighted maximum segment length. The objective of the converter placement algorithms is to minimize the overall blocking probability. Extensive simulation studies have been carried out over three typical mesh networks, including the 14-node NSFNET, 19-node EON, and 38-node CTNET. We observe that the proposed algorithms not only outperform existing wavelength converter placement algorithms by a large margin, but they also can achieve almost the same performance compared with full wavelength conversion under the same RWA algorithm.

AB - Sparse wavelength conversion and appropriate routing and wavelength assignment (RWA) algorithms are the two key factors in improving the blocking performance in wavelength-routed all-optical networks. It has been shown that the optimal placement of a limited number of wavelength converters in an arbitrary mesh network is an NP-complete problem. There have been various heuristic algorithms proposed in the literature, in which most of them assume that a static routing and random-wavelength assignment RWA algorithm is employed. However, the existing work shows that fixed-alternate routing and dynamic routing RWA algorithms can achieve much better blocking performance. Our study further demonstrates that the wavelength converter placement and RWA algorithms are closely related in the sense that a well-designed wavelength converter placement mechanism for a particular RWA algorithm might not work well with a different RWA algorithm. Therefore, the wavelength converter placement and the RWA have to be considered jointly. The objective of this paper is to investigate the wavelength converter placement problem under the fixed-alternate routing (FAR) algorithm and least-loaded routing (LLR) algorithm. Under the FAR algorithm, we propose a heuristic algorithm called minimum blocking probability first for wavelength converter placement. Under the LLR algorithm, we propose another heuristic algorithm called weighted maximum segment length. The objective of the converter placement algorithms is to minimize the overall blocking probability. Extensive simulation studies have been carried out over three typical mesh networks, including the 14-node NSFNET, 19-node EON, and 38-node CTNET. We observe that the proposed algorithms not only outperform existing wavelength converter placement algorithms by a large margin, but they also can achieve almost the same performance compared with full wavelength conversion under the same RWA algorithm.

KW - Routing and wavelength assignment (RWA)

KW - Wavelength converter placement

KW - Wavelength routing

KW - Wavelength-division multiplexing (WDM)

UR - http://www.scopus.com/inward/record.url?scp=0038038886&partnerID=8YFLogxK

U2 - 10.1109/TCOMM.2003.810834

DO - 10.1109/TCOMM.2003.810834

M3 - Article

AN - SCOPUS:0038038886

SN - 1558-0857

VL - 51

SP - 607

EP - 617

JO - IEEE Transactions on Communications

JF - IEEE Transactions on Communications

IS - 4

ER -