As soon as the line becomes free it broadcasts place

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Unformatted text preview: tar arrangement of a computer network. In this configuration, multiple computers are connected to a host computer. That is, the computers in the network are not linked directly to each other and can communicate only via the host computer. The routing function is performed by the host computer, which centrally controls communication between any two other computers by establishing a logical path between them. . Advantages 1. Star topology has minimal line cost because only n-1 lines are required for connecting n nodes. 2. Transmission delays between two nodes do not increase by adding new nodes to the network because any two nodes may be connected via two links only. 3. If any of the local computers fails, the remaining portion of the network is unaffected. Disadvantage 1. The system crucially depends on the central node. If the host computer fails, the entire network fails. Ring Network Figure 17.20 shows the circular or ring arrangement of a computer network. In this configuration, each computer in the network has communicating subordinates, but within the ring there is no master computer for controlling other computers. A node receives data from one of its two adjacent nodes. The only decision a node has to take is whether the data is for its own use or not. If it is addressed to it, it utilizes it. Otherwise, it merely passes it on to the next node. Advantages 1. The ring network works well where there is no central-site computer system. 2. It is more reliable than a star network because communication is not dependent on a single host computer. If a link between any two computers breaks down, or if one of the computers breaks down, alternate routing is possible. Disadvantages 1. In a ring network, communication delay is directly proportional to the number of nodes in the network. Hence addition of new nodes in the network increases the communication delay. 2. The ring network requires more complicated control software than star network. Completely Connected Network As shown in Figure 17.21, a completely connected network has a separate physical link for connecting each node to any other node. Thus, each...
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This document was uploaded on 04/07/2014.

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