Analysis and design of a data network for distance education for the state of Virginia

Abstract

A need exists for the State of Virginia to have a data network for its televised distance education program. A combination of a terrestrial and a satellite data network can be utilized for the purpose. The network is analyzed and its strengths and weaknesses are presented. A data protocol has been written to control such a network. Delays and throughput of the network have been calculated. The leased telephone line network can be utilized for transferring data from distant class sites to Blacksburg. Six pages of text for 75 off-campus students can be transferred from distant class sites to Blacksburg using this network, in one hour. When the terrestrial network is used for voice and data communication at the same time, a delay of approximately 30 seconds is introduced between two voice connections. This delay is too high for a distance education network. The satellite data network should be utilized for transferring data from Blacksburg to all distant class sites. A very good 19.2 kbps carrier is available with bit error rate (BER) of 1E-6 or less. A very small aperture terminal (VSAT) network has also been proposed for the purpose.