A FAIRNESS AND CQBT ALGORITHMS FOR FULL DUPLEX RING NETWORK WITH SPATIAL REUSE

Abstract

The Full duplex ring(FDR) has two modes of operation: Buffer Insertion mode for variable size packets and slotted mode for fixed size packets. As a result, this architecture is suitable for a wide range of applications and environments. Concurrent access and spatial reuse enable the simultaneous transmissions over disjoint segments of a bidirectional ring, and therefore, can increase the effective throughput, by a factor of four or more. The efficiency of this architecture does not degrade as the bandwidth and physical size of the system increases. In this dissertation, full duplex ringwith spatial reuse is implemented to enhance the throughput levels of the network. However, such a network exhibits fairness problems. Therefore Global fairness algorithm is presented, which effectively reduces the unfairness associated with such a network. One more algorithm , i.e., Check Quota Before Transmission(CQBT), is also implemented which is an efficient local flow regulation protocol. Under this algorithm, each heavily loaded station monitors its load traffic conditions to determine the access opportunities provided to its downstream neighboring stations. The comparison of these algorithms - has been presented. These algorithms are simulated in 'C' language and run • under UNIX environment.