Reducing global address recognition delays in local area networks with spatial bandwidth reuse

Abstract

A special class of local area networks have recently received much attention in which destination nodes remove packets from the network, allowing spatial bandwidth reuse or concurrent transmission of packets without collision. Destination removal requires that each node delay packets long enough so it can decode the destination address. If the address is a short label (say, 8-bit) the decoding time is short, but if we want to use global or MAC addresses of 48 or 64 bits, the sum of decoding times encountered by packets may result in unacceptably long delays, even at light traffic loads. In this paper, we propose protocols for reducing global address recognition delays which are designed to supplement existing protocols for local area networks with spatial bandwidth reuse. They are also designed to coexist with other addressing modes used for individual LANs, which are based on the use of very short, locally administered labels. Of particular interest is a completely decentralized protocol which achieves the low global address recognition delays of multi-access protocols and yet seamlessly reverts to efficient spatial bandwidth reuse at high loads. We focus on the MetaRing and MetaNet architectures and apply our methods to these local area networks. A simple probabilistic model is presented which demonstrates significant improvement in delay when our protocols are used. © 1994.