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This paper presents the first performance evaluation of the PL CEBUS with acknowledgment. Three different cases, namely, 600, 300 and 100 bit packet sizes, have been considered. The evaluation has included simulation experiments measuring message and packet delays, message throughput, and channel throughput. Acknowledged network CEBus service has been confirmed to perform well in terms of delays and message throughputs when compared to unacknowledged service over the practical range of normalized offered load. However, at high loads, substantial performance differences occur. Overall, as should be expected, the acknowledged PL CEBUS provides a more reliable service, but at the expense of somewhat increased delays and reduced throughputs when compared with the unacknowledged PL CEBUS. Detailed comparisons between acknowledged and unacknowledged networks will be presented and discussed.

The performance of a gateway which connects the CEBus to the ISDN has been investigated. The gateway handles three priority class messages for either direction. Message and channel throughputs and packet and message delays have been studied in terms of the offered load for intra-network traffic in the CEBus and inter-network traffic from the CEBus to the ISDN through the gateway. It has been found that delay for inter-network traffic for any priority level is much higher than that for intra-network traffic. In light traffic load, the delay for the ISDN to the CEBus direction is lower than that for the opposite direction. This was seen to reverse in heavy loads. In addition, significant decline of throughput was found, under the condition of large propagation delay, for all three priorities of inter-network traffic. Under favorable conditions, i.e., for low or zero propagation delay, packet length in the range of 300 to 500 bits, and light traffic, less than 70% of offered load (including inter-network traffic via the gateway), the CEBus-Gateway-ISDN system performs satisfactorily.

A theoretical formulation for the three-priority CSMA/CD protocol of the CEBus has been developed, the PAMA/PR (Priority Channel Assigned Multiple Access with Priority Resolution). It employs demand priority channel access, minimum wait time, persistent start of transmission to redress collisions, and contention resolution based on three priorities. A comparison of performance of throughput and delay of theoretical computations to simulation experiments is presented. Overall, close agreement has been found.

The CEBus has been compared to ALOHA, CSMA, and CSMA/CD media access protocols. Numerical analyses and/or simulation experiments have been used to investigate throughput and delay tradeoffs. The results of the comparisons show that the CEBus protocol with three priorities is highly efficient and well suited for its task.

A performance evaluation has been carried out by simulation experiments for a three priority CEBus router handling traffic between the PL and TP media. The message and channel throughput, and message and packet delay have been studied for a wide range of offered traffic loads. The router has behaved well, according to message priority. The inter-network traffic has showed larger delay than intra-network traffic.

This paper addresses two issues of the Consumer Electronics Bus (CEBus) implemented on the Power Line medium: the determination of (a) optimum packet length, and (b) optimum buffer size. The delay - throughput characteristics of each of the three priority classes of messages, i.e., HIGH, STANDARD, and DEFERRED, have been measured by simulation experiments for various packet lengths and buffer sizes. This way optimum packet length and buffer sizes have been deduced. The optimum packet length has been obtained by evaluating the effect of increasing packet size for a particular traffic pattern and offered load. The optimum buffer size at a node corresponds to the best overall performance for messages of all priorities in terms of overflow rates at the buffers of the nodes with respect to increasing offered loads. The optimum packet length has been found to be between 276 and 400 USTs, i.e., 184 and 276 bits. If we assign 276 USTs as the optimum packet length, the optimum buffer size at each node is found to be between 150 and 200 packets, i.e., approximately 28 to 37 Kbits.

The delay and throughput of the Consumer Electronics Bus (CEBus) with two media, Power Line (PL) and Twisted Pair (TP), interconnected through a new-type of router, a controlled router, have been investigated with three priorities HIGH, STANDARD, and DEFERRED. The controlled router aims to provide fair channel access opportunity for intra-network traffic for messages of all priorities, even in the presence of large inter-network traffic. It reduces excessive channel access by inter-network traffic through the router, even when the router is assigned HIGH priority, and maintains the delay of intra-network traffic at reasonable levels. The results of the simulation experiments have shown that the controlled router with HIGH priority achieves all its goals. The message delay of HIGH for the inter-network traffic on the PL is of larger value than that of HIGH and STANDARD for intra-network traffic at light load, and is smaller than that of the STANDARD and DEFERRED at heavy load. Moreover, the intra-network message throughputs and delays of STANDARD and DEFERRED have improved greatly, in comparison to a traditional uncontrolled router, at only a small cost in inter-network HIGH performance.

A simulated model of the proposed standard for the intelligent home computer network shows a need for design revision to accomodate heavy inter-network traffic. The Consumer Electronic Bus (CEBus), tested with the low-capacity Power Line (PL) and high-capacity Twisted Pair (TP) media interconnected through a router, performed well under minimum usage. Optimum utilization, however, led to near infinite delays in channel and message throughput as message priority was sorted. Moreover, unbalanced loading between the two media caused drastic intra-network delays.