Document Type


Date of Award


Degree Name

Master of Science in Electrical Engineering - (M.S.)


Electrical Engineering

First Advisor

Dionissios Karvelas

Second Advisor

Anthony D. Robbi

Third Advisor

Sotirios Ziavras


The Distributed Queue Dual Bus (DQDB) has become the IEEE 802.6 stan-dard for Metropolitan Area Networks (MANs). The main advantage of DQDB is that its throughput performance is not affected by the network parameters such as size, number of connected stations, or channel bandwidth. Its main drawback is that the location of the stations on the bus strongly affects their performance. For this reason a Bandwidth Balancing Mechanism (BBM_DQDB) has been proposed and in¬cluded in the 802.6 standard that can provide the requested bandwidth by the lightly loaded stations and evenly distribute the remaining bandwidth among the overloaded stations. The guaranteed bandwidth required by some applications has also mo¬tivated the recent introduction of another mechanism, the Guaranteed Bandwidth (GBW_DQDB) mechanism, that can guarantee the required level of throughput to certain high priority stations. In this thesis we first discuss the main advantages and disadvantages of BBM_DQDB and GBW_DQDB and then we introduce a new mechanism, the Guaranteed Bandwidth and Balancing Mechanism (GBBM), that combines the advantages of the previous two mechanisms and can significantly im¬prove the throughput and delay performance of the stations. We provide a detailed description of the new mechanism and we investigate its performance through sim¬ulation results. Furthermore, we compare its performance with the corresponding performance of BBM_DQDB and GBW_DQDB.