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Advantages of Bus Topology
1. Setting up bus topology is easy.
2. Bus topology requires less cabling than other topologies such as star and tree (discussed later in this section).
3. It is easy to extend the bus network since it requires connecting a new device to the cable through a tap.
Disadvantages of Bus Topology
1. When a device transmits a message, a part of the signal’s energy gets transformed into heat as it travels through
the cable, resulting in a weaker signal.
2. If the backbone cable is damaged at a single point, it will disrupt the entire network.
3. Detecting the point of fault and its isolation is problematic.
6.3.3 Ring Topology
In the ring topology, all devices are attached through a cable in the form of a ring (in circular fashion). Each device
connects to precisely two devices, one on either side. To avoid data collisions, the message to be communicated is
transmitted in one direction device by device. Each node on the path examines whether it is the intended recipient.
If not, it intensifies the strength of the incoming signal and forwards (also called transmits or relays) it to the next
node, and so on, until the message reaches the destination device. For this purpose, each intermediate node includes
a repeater (discussed in the following sections) responsible for regenerating the incoming message. In Figure 6.7, we
show a network that uses the ring topology.
Device A
Device E Device B
Device D
Device C
Figure 6.7 Ring Topology
Advantages of Ring Topology
1. Adding or removing a device is easy, requiring updating only two connections.
2. Faulty devices can be easily located and isolated.
3. Since communication is unidirectional, there is no data loss due to collision.
Disadvantages of Ring Topology
1. Since data moves only in one direction, a message sent to a device may take more time. For example, consider five
devices A, B, C, D and E laid in a ring topology. Sending a message from node A to node E, would require four hops
when the data flow is in a clockwise direction. However, the same data transfer would require only one hop in the
anti-clockwise direction.
2. Breakdown in any part of the ring will disrupt the entire network communication. If a single node fails to function,
the entire network will fail to work.
226 Touchpad Informatics Practices-XII

