Computer Networks VI

NETWORK TOPOLOGY

The topology, or the physical layout, of the network is the concern of configuration management. The three main arrangements are the bus, ring, and star as shown in Figure 1 below. In the bus configuration, each node is connected to a common cable and detects messages addressed to it. Because it is reliable and uses the least amount of cabling, this layout is often used in offices. However, fiber-optic systems cannot usually be arranged this way.

In the ring layout, packets of information are retransmitted along adjacent nodes. It has the possibility of greater transmission distances and fiber-optic systems can use this layout. However, the components necessary can be more expensive. A popular implementation of ring topology is IBM's Token Ring configuration.

In the star arrangement, all traffic is routed through one central node. It offers the advantages of simplified monitoring and security. Also, unlike the other layouts, the failure of one node, unless it is the central one, does not cause the entire network to fail. This drawback is addressed in the clustered star layout, in which a number of star networks are linked together.