A bandwidth management scheme for handling asynchronous and isochronous traffic in a LAN/MAN environment

A metropolitan area network (MAN) based upon the dual queue distributed bus (DQDB) standard [IEEE 802.6] provides a medium access scheme, which offers two service classes. The queue arbitrated (QA) medium access part may be used for packet service, whereas the prearbitrated (PA) medium access part is used to serve semipermanent connections having constant bit rates (n×64 kbit/s). This paper proposes a novel solution for the allocation and the balancing of the bandwidth shared by users of the two service classes taking into account the access rate limitations known by SMDS networks. Its centralised approach is based on a manager-agent communication scheme. The bandwidth manager, as part of the network manager, receives all bandwidth changes, performs the proposed bandwidth allocation algorithm and, depending upon the results, distributes the necessary parameter to the involved agents to ensure the allocation of the bandwidth. The algorithm employed prioritises the PA service user over the QA service user