Advantages and disadvantages of network topologies | bus,star,ring
This page mentions benefits or advantages of network topologies viz. bus, star and ring and drawbacks or disadvantages of network topologies.
What is network topology ?
It describes ways in which elements of a network are mapped i.e. physical and logical arrangements of network nodes. In other words network topology refers to configuration of cables, computers and other peripherals.
Types of Network Topologies
Following are the types of network topologies.
• Bus topology
• Star topology
• Ring topology
• Mesh topology
• Tree topology
• Hybrid topology
Let us understand Advantages and disadvantages of network topologies which include bus network, star network and ring network topology.
Advantages of Bus network topology type
All the nodes are connected by single cable in bus network topology type.
The cable starts from the node and terminates on the other end.
Example: LAN network
Following are the advantages of Bus network topology type:
➨It is cheap, easy to install and easy to implement.
➨It requires less cable work.
➨It is best applicable for small networks such as LAN.
➨Any two stations communicate directly without interference or assistance of any other node or nodes.
➨Any extra nodes can be added without any disruption of the services.
➨It uses coaxial cable or twisted pair due to transmissions in both the directions.
➨It provides fastest speed due to direct communication between nodes.
Disadvantages Bus network topology type
Following are the disadvantages of Bus network topology type:
➨The cable length is limited and hence it limits number of stations supported by bus network.
➨As mentioned it performs well for limited number of nodes.
➨Fault isolation is difficult.
➨Suffers from signal reflections at ends and at joints. This needs to be plan appropriately.
➨Optical fiber based bus network needs bi-directional optical couplers to perform two way communication.
Advantages of Star network topology type
In star network each node is connected to a central device known as Concentrator or Hub. Nodes can be file server, work stations and peripherals. Here hub receives the signal from any node and passes it to all the other nodes on the network.
The data on star network passes through the hub/switch/concentrator before continuing to the destination. The Hub/switch/concentrator manages as well as controls the functions of the network/
Following are the advantages of Star network topology type:
➨All the nodes are connected with central node. Hence it reduces chances of complete network failure. Only the faulty nodes need to be repaired.
➨It is easy to manage.
➨It is easy to install and wire the nodes.
➨It is easy to locate the problems.
➨It is easy to expand compare to bus and ring network topologies.
Disadvantages Star network topology type
Following are the disadvantages of Star network topology type:
➨It requires more cable length compare to linear topologies.
➨If the hub or concentrator fails all the attached nodes are disabled. Redundant hubs are kept for such critical situations.
➨It is more expensive due to cost of concentrators.
Advantages of Ring network topology type
All the nodes are connected end to end to form loop. Here each node has connection with two other nodes one to left and the other to right of it. Here there is no central node and all the nodes have some contol functionalities. They identify their own address and also does retransmission. The message format consists of destination node address followed by data payload.
A token (known as small data packet) is passed around the network continuously. When a node needs to transmit, it reserves the token for next trip around and attaches its data packet to it.
Following are the advantages of Ring network topology type:
➨It is easier to manage and hence fault isolation is easy and straightforward.
➨It has lowest cost among all the network topologies.
➨It is very orderly network where every device has access to the token and opportunity to transmit.
➨It provides good communication over longer distances.
➨It handles traffic with high volume.
Disadvantages Ring network topology type
Following are the disadvantages of Ring network topology type:
➨The failure to any cable or node will break the entire network down. This also takes more time to restore the network.
➨Any extra node is added after shutting down the entire network and hence will disrupt the services to the operational nodes.
➨It provides slowest speed as nodes are accessed sequentially.
➨The movement or change made to any nodes will affect the performance of the entire network.