Bus Topology in detail with Example

Equipment used in Bus Topology:

• A common bus also called Channel it is the backbone cable (coaxial cable) used for communication.
• Taps are connectors (BNC T connectors) that are used to connect computers or other devices with Bus (backbone).
• BNC Plug It is a plug used at the computer side to connect it with the dropline. 
• Droplines are the cables used to connect the computer with a backbone.  one end of the droplines is connected with a BNC T connector to connect with backbone and other end is connected with a BNC plug to connect with computer. 
• Terminator these are endpoints of Bus.

It is the simplest form of topology, the main cable also called Bus or backbone cable is used as a backbone communication source between all connected devices at the same line. Taps (BNC T Connectors) and droplines are used to connect computers with the main cable (Bus). In this topology, the main cable is the only single line source that is used for transmission between all connected devices.

Example:

The Scenario is that Computer A in this example wants to communicate with Computer D, for this purpose it will send a message to Computer D through the main channel (Bus), all other connected computers and printers will also listen to this message, check their mac address (physical address) if they found it in the data frame the message will be accepted otherwise they refuse the message as in our example the message is only for Computer D so the Computer D will only the one who will find its mac address in a data frame and accept the message.

As we can see in the example diagram the communication between Computer A and Computer D is highlighted with green arrows the message is being accepted sent by Computer A. Computer B, Computer C, and the printer refused to accept the message shown with the red arrow. At the endpoint, terminators are dropping the data frames as it is the termination point of the Backbone Bus indicate by the blue arrow.   

In Bus topology data is move in one direction when it reached the end (termination point) of the main cable (Bus), the terminator will drop the data from Bus to end the communication process or in other words to prevent data flow disruption.

Advantages of Bus topology:

It is very simple to install and configure. If one point or node fails others will not be affected. Cabling cost is not too much as only one channel (main cable) is used for the transmission of data.

Disadvantages of Bus topology:

It is not as efficient as, only the limited devices could be connected in one bus increasing the nodes will also affect its efficiency and will be the cause of slow working. In case if the main cable called bus fails the whole network will go down. Security risks are all also present in it because of broadcast as the messages were sent by one user on the bus have to listen to all connected computers. Congestion will also be the cause of slowness or data failure because of the only communication source for all connected devices.