Destination stripping dual ring: a new protocol for MANs

A new MAC protocol for ring-topology Metropolitan Area Networks (MANs) is defined. Starting from an analysis of ring-topology networks and of current MANs, guidelines for the definition of high performance MAC protocols are derived. The DSDR (Destination Stripping Dual Ring) protocol is defined applying these guidelines. Its key characteristics are the dual-ring topology and the destination stripping capability which, together with multiple tokens, slotted operation and other details, give DSDR very high performance, mainly in terms of total throughput, guaranteed throughput per station and maximum access delay. The protocol parameters can be tailored for different compromises between guaranteed throughput for delay-sensitive applications and total throughput. On each of the two rings, guaranteed throughput, with bounded access delay, can be close to twice the medium capacity under worst case hypotheses, while total throughput, under realistic hypotheses, can be close to four times the medium capacity. The maximum interval between accesses by the same station can be as low as N/2 slot times, with N stations on the network. Multicast can be supported with the same simplicity and the same cost as in other LANs and MANs. © 1992.