Interconnection of random access packet switching networks

Date of Completion

January 1987


Engineering, Electronics and Electrical




The first part of this study is concerned with 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. For the multiplexing of the user transmissions and the bridge node transmissions on the available broadcast channel in each network, frequency division, and contention are considered. The throughput-delay characteristics of the interconnected system, operating under the above multiplexing techniques, are found and comparisons are made. It is shown that contention multiplexing can yield system performance comparable to that of frequency division multiplexing, while requiring no hardware or software modification of either network.^ The second part of the study deals with another interconnected system similar to the first in that it is comprised of two random access packet switching networks, connected via a heirarchical structure employing bridges. The second system differs from the first in that the modulation technique employed makes possible the use of Code Division Multiple Accessing (CDMA). The use of CDMA allows for the simultaneous successful transmission of multiple packets within each network. The effects on the system's throughput-delay characteristics, of allocating multiple transceivers to the bridges, is explored. It is shown that while such allocation makes no sense in narrow band (single channel) networks, a substantial performance improvement can be realized in CDMA systems. ^