| Summary: | 碩士 === 國立高雄應用科技大學 === 資訊工程系 === 97 === Abstract
The ring architecture is one of popular network topology for metropolitan area networks (MANs). All of access points (APs) are connected on one fiber to drop or add data in the ring network and one or many local area networks (LANs) are usually connected to each AP. That is, the incoming traffic loads from LAN to AP is not same in the moment. So that the total traffic loads of LAN (or LANs) into each AP is serious asymmetric on the real network world. However, most researches are regarded as symmetrical load in the published papers. Therefore, this thesis is interesting to study the performance difference between symmetric and asymmetric traffic loads for all-optical metro ring networks.
In this thesis, two MAC protocols of multi-token ring and beforehand bandwidth reservation (BBR) ring based on reserve the empty slots in the next big-slot cycle are studied to analyze the performance influence under symmetric and asymmetric traffic loads for metro ring networks. To evaluate and compare the utilization difference of channel bandwidth under symmetric and asymmetric traffic loads scenario, the BBR-ring with three kinds of different packet scheduling is studied based on time slot scheme. Besides, the node architecture of two different MAC protocols must use same transceiver, i.e., one tunable transmitter and fixed receiver (TT-FR) for add/drop data, and one fixed transmitter and fixed receiver (FT-FR) for add/drop control message. According to simulation results, the BBR ring using the statistic TDM approach achieves the best bandwidth utilization under symmetric or asymmetric traffic loads, while the multi-token protocol achieves the worst performance. However, the system performance of BBR-ring and multi-token ring are serious drop off about 100% under asymmetric traffic load than symmetric traffic loads. The contribution of this thesis is really to understand the efficiency of the real metro network, and then integrates the all-optical metro networks and access networks (e.g., passive optical networks) for the next generation optical networks.
Keywords: Metropolitan Area Network (MAN), Local Area Network(LAN), Asymmetric Traffic Load, Multi-token Ring, BBR-ring, Statistic TDM, Passive Optical Network (PON)
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