The client/server way to interconnect high-speed LANs

A client/server implementation of the source-routing protocol suitable for the high-speed LAN interconnection is described. Compared to the standards, it overcomes the high processing overhead imposed on spanning tree bridges, as it minimizes the route discovery overhead induced by the source routing in complex topologies. In a classical way, the source station supplies the routing information, but each station does not itself have to explore the topology. When the destination station is unknown, it sends a Request frame to the server that replies by a Response frame containing the requested routing information. To be easily adaptable to the topology evolution, the server uses a routing acquisition process, resulting in the knowledge of the interconnection, and a station acquisition process that indicates the identifications of stations attached on a segment. To preserve transparency, the localization of the server is hidden. Thus we make easier the insertion of new stations or bridges, as the recovery of element failures is facilitated. Operations and resources of the proposed protocol are described. The adaptation of the client/server mechanism is checked using an event-based simulation. Comparisons with source routing show that it obtains a greater improvement, in terms of network throughput, as the number of elements increases. (C) 1997 Elsevier Science B.V.