DQDB-an access delay analysis

The distributed queue dual bus is a protocol being considered by the IEEE 802.6 Working Committee for adoption as a metropolitan area network standard. Its primary function is to interconnect LANs over a high-speed physical medium (optical networks) operating at over 100 Mb/s and to support integrated traffic. Although DQDB is a totally distributed and contention-free protocol with throughput very close to one, the access delays experienced by stations vary with their position on the bus, upstream stations on a particular bus experiencing lesser delays compared to downstream stations. The results of simulation runs that compare the access delays experienced by MAC (media access control) stations at different utilization levels and at different priority levels are presented. It is noted that skewing in access delays is experienced by downstream stations