Interconnection of CSMA Local Area Networks: The Frequency Division Approach

This paper considers the interconnection of two local area networks, each of which connects a large population of users via a carrier-sense multiple-access (CSMA) channel. In each network a bridge node receives internetwork packets from the local users and forwards them to the bridge node of the other network via a point-to-point link; the bridge node of the destination network queues these internetwork packets for subsequent broadcasting to the local users. The available broadcast channel in each of the two networks is frequency divided into a bridge node subchannel, used for bridge node transmissions, and a CSMA user subchannel, used for user transmissions. For the interconnected system, stability conditions, optimal bandwidth allocations, and throughput delay characteristics are found. Also it is shown that the performance of a single CSMA network can be substantially improved by partitioning it into smaller interconnected networks.