UBC Theses and Dissertations
Communication protocol channel utilization and the design of the MAX2 data link protocol Lee, Kenneth
In this thesis, we first surveyed and analyzed the Kermit, XMODEM, YMODEM, and ZMODEM file transfer protocols. A number of theoretical channel utilization equations were then developed that would predict the effective utilization, and hence effective throughput, of stop and wait protocols and streaming protocols. A series of experiments were performed that measured the effective throughput of the protocols at various baud rates and error rates and showed the utilization equations to be within ±5% of the measured values. Based upon these results, a full-streaming communications protocol, MAX2, was designed. A subset of the MAX2 protocol was then implemented and tested at different baud rates and error rates. These results were within ±1.5% of the theoretical values and showed that the MAX2 protocol to be more efficient than the Kermit, XMODEM, YMODEM, and ZMODEM protocols at all baud rates and error rates when using comparable maximum packet sizes . These results also indicated that in order to achieve maximum effective throughput, the packet size must change as the communication channel's error rate changes.
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