Sinha 1997 ieee 1 geographic distribution the main

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Unformatted text preview: computer of such a network has a direct dedicated link, called a point-to-point link, with all other computers in the network. The control is distributed with each computer deciding its communication priorities. Advantages 1. This type of network is very reliable, as any link breakdown will affect only communication between the connected computers. 2. Each node of the network need not have individual routing capability. 3. Communication is very fast between any two nodes. Disadvantage 1. It is the most expensive network from the point of view of link cost. If there are n nodes in the network, then (n-l)/2 links are required. Thus, the cost of linking the system grows with the square of the number of nodes. Multi-access Bus Network Figure 17.22 shows a multi-access bus network. In this type of network, a single transmission medium is shared by all nodes. That is, all the computers are attached to the same communication line (channel). When a particular computer wants to send a message to another computer, it appends the destination address to the message and checks whether the communication line is free. As soon as the line becomes free, it broadcasts (place) the message on the line. As the message travels on the line, each computer checks whether it is addressed to it. The message is picked up by the addressee computer, which sends an acknowledgement to the source computer and frees the line. This type of network is also known as 'multipoint' or 'multidrop' or 'broadcasting' network. It is appropriate for use in a local area network where a high-speed communication channel is used and computers are confined to a small area. It is also appropriate when satellite communication is used as one satellite channel may be shared by many computers at a number of geographical locations. Advantages 1. The main advantage of a multi-access bus network is the reduction in physical lines. 2. The failure of a computer in the network does not affect the network functioning for other computers. 3. Addition of new computers to the network...
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