Summary: | 碩士 === 國立高雄第一科技大學 === 資訊管理所 === 97 === Nowadays optical networks have been enhanced the overall capacity because of the maturity of WDM technology. However, the wavelength continuity constraint in WDM networks prevents network resources from being fully utilized and hence results in high blocking probability. To improve the blocking probability, how to devise an effective routing and wavelength assignment(RWA) algorithm becomes an important issue. Some previous works show that FPLC can reduce the blocking probability effectively but make routing decision costly because it needs complete wavelength information and hence results in high setup delay and complex control overhead. FPLC-k, FPLC’s variant, only needs neighborhood information of few first k links of routes to make decision, but tradeoff higher blocking probability since less wavelength information is considered. In this dissertation, we propose a new dynamic routing algorithm, threshold-based least congestion routing (TLCR). This algorithm can reduce setup time and control overhead without sacrificing blocking probability. The experiment results show that TLCR has the same performance as FPLC in blocking probability and but is more flexible in routing decision than FPLC-k. Therefore, it can work under the requirement of low setup delay and control overhead. Some experiments with sparse wavelength converter placement also show that TLCR is comparable with FAR and LLR in terms of blocking probability.
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