The issue of routing in interconnected local area networks (LAN's) is considered. Of particular interest is Source routing where the source station specifies, in an inter-LAN frame, the complete path traversed by that frame. In source routing, a mechanism is needed for the source station to determine a path to any given destination. A pathfinding algorithm has been proposed by Sy, Pitt, and Donnan. In this paper, we evaluate the performance of that algorithm using a simulation model of interconnected token rings. Our evaluation is based on a connection-oriented environment and the assumption that the pathfinding algorithm is used each time a new connection is established. Our results indicate that the algorithm selects paths with good delay and throughput performance for the new connection. As to the existing connections, the algorithm yields good throughput behavior, but may not perform well as far as delay is concerned.

The use of channel scheduling to improve a measure of fairness in packet-switching networks is investigated. This fairness measure is based on mean end-to-end delays derived from Kleinrock's classical model. The network designer can incorporate any desired relative delay among user classes into this fairness measure. It is found that scheduling is helpful in reallocating delay among user classes and can be used to improve the fairness of a network. It is also shown that a parameterized queueing discipline can be used to further improve fairness. A conservation theorem characterizing the effects of scheduling on overall mean end-to-end delay is established. The results are applicable to both fixed and random routing and are found to be relatively insensitive to fluctuations in traffic.

CCITT has proposed Recommendation X.75 as a technique for interconnecting public data networks in a standard way. However, this is not the only or necessarily the best approach. This paper focuses on two major factors in determining the merits of different network interconnection approaches, and compares the X.75 approach to a few alternatives in each of these areas.

The choice of collision control algorithm has an effect on the performance of Ethernet. A linear incremental backoff algorithm is proposed and its performance is compared to the binary exponential backoff algorithm. Two variations of Ethernets are used in the comparison: one treats data and acknowledgement packets equally; the other gives priority to acknowledgement packets. The maximum throughputs achieveable by both variations are derived. The performance of both variations is then evaluated by discrete simulation. The evaluation is based on a Ethernet model with uniform or biased traffic.