What is Star Topology in Computer Network

Any network topology is defined by the physical configuration as well as logical mapping of the data flow between the nodes in the network. Topology can be understood as the shape or structure of a network. This shape does not necessarily correspond to the actual physical design of the devices on the computer network.

Star Topology:

Star topology is a type of network topology where each computer/host is connected to a central device, known as hub device, using a point to point connection (from hub to PC).

In star topology each host is not only connected with hub, but other computers are connected together via networking terminology. Hosts can communicate with each other via hub.



Advantages and Disadvantages of Star Topology:

As consider to the bus topology a cable is broken the whole network is destroyed. Here hub act as single point of failure in star topology. In star topology if hub fails connectivity between hosts fails.

Advantages of Star Topology:

  1. It has two means to prevent problems.
  2. It allows all nodes to communicate with each other conveniently.
  3. No disruptions to the network when connecting or removing devices.
  4. Any host cable is broken other nodes will not get affected.
  5. Easy to detect faults and to remove parts. 

Disadvantages of Star Topology:

  1. If the hub, switch, or concentrator fails, nodes attached are disabled. Communication between entire host will be lost and network will fail.
  2. It is expensive, since it requires more cable than the bus and ring topology.
  3. The cable travels separately from the hub to each computer.
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Signal Movement in Ring Topology:
The token or signal move in ring topology between two adjacent devices so this message that is in form of token can start its propagation on ring  in clockwise direction or anti clock wise direction.

Star Topology Cost in Networking:
Star topology is not much expensive, let's suppose to connect another host we need only 1 cable and the configuration of star topology is simple.

Central Device in Ring Topology:
A hub which connects all the devices together is called central device. The hub can be of following type:
  • Hub or Repeater: type of Layer 1 device which work on Physical Layer.
  • Switch or Bridge: Type of Layer 2 Device, usually work on data link layer.
  • Router or Gateway: Layer 3 devices or simply network layer devices.

Ring can Extend to Large Area:
All devices are connected to one another in the shape of a closed loop. Ring topologies are relatively expensive and difficult to install, but they offer high bandwidth and can span large distances.

Dual Ring in Ring Topology:
It is one of the disadvantages of Ring Topology that a break in the ring can stop the whole communication process. So, to prevent from this situation Dual Ring Topology is used in which two rings connect each node on a network. One is used as a primary ring and other as a backup in case of failure of primary ring.

Efficiency of Ring Topology and Delay:
In ring topology “Communication delay is directly proportional to number of nodes in the network”. It means as the number of nodes increase communication delay increases, chances of data loss and corrupt become more and also the cost to maintain network increases so ring topology is feasible over the network where number of nodes are less.


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