Computer Network Topologies & It types

 

What is Network Topology or LAN Topology?

Network topology is the arrangement of the elements (like nodes, links, etc.) of a communication network. Network topology is the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses, and computer networks. There are mainly two types of topology: physical and logical topology.

In physical topologies, there are various types of topologies. They are point-to-point, Bus, Star, Ring, Mesh, and Tree Topologies.

Bus Topology

A bus topology is a topology for a Local Area Network (LAN) in which all the nodes (bridges, switches, routers, modems, etc.) are connected to a single cable. The cable where the nodes are connected is also known as the backbone, RJ-45 network cable, or coaxial cable. 

Advantage of bus topologies:

1. It’s easy to install or setup.

2. Bus topology required less cable compared to other topologies.

3. If one device fails, then the other devices are not impacted. 

4. It works efficiently for small networks.

5. It is easy to understand bus topology.

The disadvantages of bus topology include:

1. The bus topology is very slow as compared to other topologies. 

2. It is not suitable for large networks. 

3. Termination is required to prevent bouncing of signals. 

4. In the event of any device failure, it is difficult to find faults in a network, in case of any device failure.

5. If the backbone cable is damaged, then the entire system fails. 

6. The length of cable is limited.

Ring Topology

A ring network is a network topology in which each node is connected to each other node. Data is transferred from one node to another node, with each node handling a packet as it passes.

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A ring topology is a network configuration where device connections create a circular data path. Each network device is connected to each other like points on a circle. In a ring topology, packets of data travel from one device to another until they reach their destination.

Ring topologies may be used in either LANs (local area networks) or WANs (wide area networks). Depending on the network card used in each computer of the ring topology, a coaxial cable or an RJ-45 network cable is used to connect computers together.

There are two types of ring topology. 

1. unidirectional 

2. bidirectional

Unidirectional

In unidirectional ring topology, data travels in one direction only, either clockwise or anticlockwise. A half-duplex network is also called a unidirectional ring topology.

Bidirectional

In a bidirectional ring topology, data travels in both directions. A bidirectional ring topology is also called a full-duplex network.

Advantage of ring topology

1. Reduced chances of data collision.

2. Equal access to all the resources. 

3. The token passing system makes the performance of the ring topology better than the bus topology under heavy traffic. 

4. In a ring topology, there is no need for a server to control the connectivity among the nodes in the topology. 

5. It is cheap to install and expand.

Disadvantage of ring topology

1. In a unidirectional ring, a data packet must pass through all the nodes. 

2. It is difficult to troubleshoot the ring topology. 

3. In order to communicate with each other, all the computers must be turned on. 

4. Fully dependent on one cable. 

5. If one workstation shuts down, it affects the whole network. Or if a node goes down, the entire network goes down.

Star Topology

A star topology is a network topology in which all the network nodes are individually connected with a central hub, switch, or computer that acts as a central point of communication to pass on the messages. In star topology, there are different nodes called hosts, and there is a central point of communication called a server or hub. Data on a star network passes through the hub before continuing to its destination. The hub manages and controls all functions of the network. It also acts as a repeater for the data flow.

Advantage of Star topology:

1. Devices can be removed or added without disturbing the other network. 

2. If one node connection breaks, it does not affect the other computer nor their connections. 

3. It's easy to add a new node or station. 

4. It's easy to troubleshoot and monitor the network.

5. No data collisions can occur because each device is controlled by hub.

Disadvantages of Star Topology:

1. If the central point fails (hub or switch) then the whole system will fail. 

2. Star topology requires more cable compared to bus topology. 

3. Extra hardware (hubs or switches) is required, which adds to the cost. 

4. It requires skilled full technicians because cable installation is more difficult.

5. There is no route redundancy

Mesh Topology

A mesh topology is a type of network topology where each network node is directly connected to most of the other nodes. where data and information are passed from one node to another. If one node fails, then the data will simply take another route to reach its target destination.

 There are two types of mesh topologies.

1. wired mesh/ Fully connected mesh topology

2. Wireless Mesh/ Partially connected mesh topology

wired mesh/ Fully connected mesh topology

In a full mesh topology, each node is connected directly with all other nodes.

Wireless Mesh/ Partially connected mesh topology

In a partial mesh topology, only some of the nodes are connected to each other.

Advantage of mesh topology 

1. Adding new devices won't disrupt data transmissions. 

2. A mesh topology provides high privacy and security. 

3. It is easy to diagnose the faulty device. 

4. Troubleshooting of this topology is easy as compared with other types of networks. 

5. Each connection can carry its own data load 

Disadvantage of mesh topology

1. Installation and configuration are difficult. 

2. Many connections require a lot of maintenance. 

3. Adding or removing a computer is difficult. 

4. It consumes a lot of power.

5. It is difficult to install and manage.