A Highly Adaptive Media Access Protocol for Dual Bus Metropolitan Area Networks

The Distributed Queue Dual Bus protocol, the media access protocol of the current I E E E 802.6 standard for Metropolitan Area Networks, has two major drawbacks. First, it is not able t o utilize the full bandwidth. Also, it needs considerable t ime until a f a i r distribution o f bandwidth t o the stations is achieved. I n this study a protocol for dual bus networks is proposed which does not show the disadvantages inherent t o the I E E E 802.6 standard. A fa ir distribution of bandwidth is obtained after a t ime equal t o one round-trip delay. Additionally, the protocol allows a full utilization of the available bandwidth. The protocol is derived f rom a so-called yair and waste-free bandwidth allocation’ scheme. The features of the new protocol can be included into the the existing I E E E 802.6 standard. By comparing the performance of the newly proposed protocol with the I E E E 802.6 standard (including bandwidth balancing) we show that the new protocol has significant advantages over I E E E 802.6.