The widespread introduction of Local Area Network (LAN) media has had profound implications for communications protocols. It is required that the campus network at Hatfield, which since 1981 has been based on the cambridge Ring, should take advantage of the properties of their LAN, should meet the demand of both new and traditional applications and should allow network interconnections. To show how these requirements might be met a review is given of the communications support provided elsewhere by data transportation protocols. Expansion is also required, but it may not be achieved unless appropriate planning decisions are made. Measurements which provide knowledge of typical traffic characteristics and quantities and of constraints or erroneous behaviour which may affect the decisions made are required. This information will allow modellers and planners to make predictions and estimates so that future demands can be met. A monitor tool has therefore been developed. It allows the traffic of the network to be monitored and measurements to be retrieved, displayed and analysed. A decentralized approach which provides an integrated measurement facility has been adopted. The design, and the decisions and constraints which influenced that design, are desribed. From the measurements gathered a comprehensive traffic characterization is provided. It relates traffic characteristics of different grains to applications, to system characteristics and to constraints. The measurement analysis therefore establishes a firm base from which predictions and estimates may be made. It also provides a base for comparisons, one which allows the effects of hardware and software changes to be observed and which also provides valuable information to both planners and modellers of similar and different environments. Implementation errors and erroneous behaviour are demonstrated and their cause is established. A bottleneck is identified, performance thresholds are determined and protocol modifications are suggested. Specific traffic characteristics are identified for particular applications and user groups, effects of different buffer sizes are considered and relationships between protocol efficiency and traffic patterns are discussed
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:373446 |
| Date | January 1986 |
| Creators | Vassiliades, S. |
| Publisher | University of Hertfordshire |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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