In telecommunications, a distributed-queue dual-bus network (DQDB) is a distributed multi-access network that (a) supports integrated communications using a dual bus and distributed queuing, (b) provides access to local or metropolitan area networks, and (c) supports connectionless data transfer, connection-oriented data transfer, and isochronous communications, such as voice communications.
To appreciate the innovative value of the DQDB MAC algorithm, it must be seen against the background of LAN protocols at that time, which were based on broadcast (such as IEEE 802.3 Ethernet) or a ring (like IEEE 802.5 Token Ring and FDDI).
This improves reliability which is important in Metropolitan Area Networks (MAN), where repairs may take longer than in a LAN and Wi-Fi because the damage may be inaccessible.
in entire cities, with lengths that reach up to 160 km (99 mi) with speeds of a DS3 line (44.736 Mbit/s).
This article incorporates public domain material from Federal Standard 1037C.