The DQDB protocol-what about fairness?

The author studies fairness issues of the distributed queue dual bus (DQDB) protocol, which is the draft of a standard proposed by IEEE 802.6 for metropolitan area networks (MANs). He shows that DQDB yields fair medium access for many realistic scenarios. It is found that DQDB is unfair in subnetworks interconnecting few stations and covering large distances. This scenario shows the limits for backbone networks interconnecting few stations scattered over large areas. For this special application, DQDB is questionable. Allocation of dedicated bandwidth (prearbitrated service) may be an appropriate solution.<>