network topology definition, types

What is Network Topology? Definition, Types, and Pros/Cons

What is Network Topology?

Network topology refers to the way in which the nodes of a network are linked together. It determines the data paths used between any pair of nodes in the network. Some types of network topologies are as follows:

  • Star topology
  • Ring topology
  • Bus topology
  • Tree topology
  • Mesh topology

Star Topology

In the star topology, each device is connected point-to-point only to the central controller usually called HUB.

In this topology, if a device wants to send data to another, at first it sends the data to the central controller then it relays the data to other connected devices.

star topology
Star topology

Some advantages (merits) and disadvantages (demerits) of star network topology are as follows:

Advantages:

  • Less cabling is required.
  • Less expensive.
  • Easy to install and re-configuration.
  • If one node fails due to some reason it does not affect the entire network.

Disadvantages:

  • If the central HUB fails then the whole network fails to operate.
  • An additional device is necessary to rebroadcast.

Ring Topology

In-ring topology there is no central controller or HUB. In this topology, a signal is passed along the ring in one direction from device to device (or node to node) until it reaches its destination.

ring topology
Ring topology

Some advantages and disadvantages of ring network topology are as follows:

Advantages:

  • No central controller is necessary.
  • The required cable is less.
  • Inexpensive.

Disadvantages:

  • The data travels in only one direction from node to node around the ring.
  • If a link is a failure the entire network is also failing.

Bus Network Topology

A bus topology is a multi-point topology. One long cable acts as a backbone to link all the devices in the network.

Computers are connected to the bus by drop lines and taps. A drop line is a connection running between the devices and the main cable.

A tap is a connector to connect devices to the main cable. At both ends of the cable, terminators are used. In this topology, the message travels in both directions of the cable.

bus topology
Bus topology

Some advantages and disadvantages of bus topology are as follows:

Advantages:

  • Easy to set up.
  • The required cable is less.
  • One node failure does not affect the entire network.
  • Inexpensive.

Disadvantages:

  • Data traffic is high. Hence, the collision rate is also high.
  • A break in the bus cable stops all transmissions.

Tree Topology

The tree topology is a widely used approach in data communication. It is similar to bus topology except that the transmission lines are divided into several wires.

tree
Tree topology

The advantages and disadvantages are the same as a bus topology.

Advantages:

  • Easy to set up.
  • The required cable is less.
  • One node failure does not affect the entire network.

Disadvantages:

  • Data traffic is high.
  • A break in the bus cable stops all transmissions.

Mesh Topology

In a mesh topology, each station is connected to every station in the network. It is used in a network, that does not have a large number of nodes involved.

mesh
Mesh topology

Advantages and disadvantages of mesh network topology:

Advantages:

  • Very fast data communication due to full connectivity.
  • If one link becomes unavailable, it does not affect the entire network.

Disadvantages:

  • Installation and reconfiguration are difficult.
  • The required huge amount of cabling. Hence, it is expensive.
  • Fault isolation is difficult.

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