This thesis gives an approximate analytical solution in terms of mean
end-to-end delay of a system of token-ring local area networks
interconnected via a backbone ring. The solution is based on an existing
approximation (see chapter 2) of the mean end-to-end delay in a
stand-alone token ring LAN, and it is extended by approximating the
arrival rates at the bridges (that are function of the throughput of each
subnetwork and the percentage of it that is directed to the other
subnetworks). A new packet-length distribution is defined and its
detailed derivation is described in Appendix B.