A General Bandwidth Allocation Scheme for Multi-Priority Traffic on DQDB Networks

The Distributed Queue Dual Bus (DQDB) Media Access Control (MAC) protocol, the current IEEE 802.6 standard for Metropolitan Area Networks, functions well only for one priority level even when three priority levels are designed to support multi-priority traffic. In this paper, a general and flexible bandwidth allocation scheme for handling the multi-priority traffic is proposed. In this scheme, the entire bandwidth can be shared by different priority levels according to a pre-specified ratio. For any absent priority level, the corresponding pre-allocated bandwidth will be automatically reallocated to other priority levels. This scheme is also rather suitable for solving the bandwidth domination problem, the priority domination problem, the priority capturing problem, and the bandwidth allocation problem of the DQDB networks which are unable be effectively solved by the standard DQDB protocol with the bandwidth balancing mechanism.