期刊名称：International Journal of Computer Science and Network Security
印刷版ISSN：1738-7906
出版年度：2006
卷号：6
期号：8A
页码：197-207
出版社：International Journal of Computer Science and Network Security
摘要：In metropolitan optical networks, the fairness issue has mostly been analyzed with regard to synchronous transmission (i.e., slotted WDM ring). In this context, we focus on the performance of asynchronous CSMA/CA protocol with variable packet sizes. We examine the fairness issue arising between ring nodes sharing a common data channel and show that the asynchronous CSMA/CA protocol suffers from bandwidth fragmentation and positional priority fairness problems. The paper proves that the phenomenon of bandwidth fragmentation represents the most important issue in asynchronous CSMA/CA protocol because it leads to bandwidth waste and, thus, increases unfairness for certain ring nodes. In this regard, we explore limitations of a previous proposed solution, the so-called Traffic Control Architecture using Remote Descriptors (TCARD). Afterwards, we present an algorithm, called Smart sPACEd tranSmission (SPACES), which deals with the aforementioned fairness problems. The devised scheme is based on a statistical and fully distributed mechanism to grant fair access to shared resources. As illustrated in this article, SPACES algorithm alleviates performance degradation and resources underutilization while achieving fairness among ring nodes.
关键词：Asynchronous optical CSMA/CA protocol, Variable length packet, Shared bus ring network, Distributed fairness algorithm, Bandwidth fragmentation, Performance.
