Why is star topology better than ring topology?

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There are number of topologies in computer networking, star topology, ring topology, bus topology and mesh topology.

Difference Between Ring Topology & Star Topology

In star topology multiple nodes can only do their communication by using a central hub whereas in ring topology there is a direct communication link between two nodes, No central technology use that transfer their data.

Ring Topology

• Cable forms closed ring or loop with all computers and devices arranged along ring.
• Data Travels from device to device around entire ring, in one direction.
• Primarily is used for LAN’s but also is used in WAN’s.

Ring Topology Advantages:

• Data is quickly transferred.
• The transmission of data is relatively simple as packages travel in one direction only. 

Ring Topology Disadvantages:

• Data packets must pass through every computer between the sender and recipient therefore, this makes it slower.
• If any of the nodes fail then the ring is broken and data cannot be transmitted successfully.
•  It is difficult to troubleshoot the ring.

Ring Topology

Star Topology

A type of topology where CPU’s are connected via medium called hub. A topic which you need to read on Star Topology.

• All devices connect to a central device, called hub.
• All data transferred from one computer to another passes through hub. 

Star Topology Advantages:

• Easy to install and wire.
• Security can be implement in the hub/switch.
• Easy to detect faults and to remove parts.

Star Topology Disadvantages:

• Requires more cable length than a linear topology.
• If the hub or concentrator fails, nodes attached are disabled.
• More expensive than linear bus topologies because of the cost of the concentrator. 

Star Topology

A topology is a relationship exist between the links and linking devices [nodes] to each other which is represented by a geometric representation. Star and Ring topology are the types of network topologies. The crucial difference between star and ring topology is that the star topology is suitable for a primary-secondary type of connection whereas ring topology is more convenient for the peer-to-peer connection.

The link is shared equally in the peer-to-peer connection. Inversely, in a primary-secondary relationship one device is used to control traffic and other devices must transmit the signal through it.

Content: Star Topology Vs Ring Topology

1. 1. Comparison Chart
   2. Definition
   3. Key Differences
   4. Conclusion

Comparison Chart

Basis for comparisonStar TopologyRing Topology

Architecture structure	Peripheral nodes are linked to the central device known as a hub.	Every node has two branches connected to a node either side of it.
Amount of cabling required	Larger	Less as compared to star topology
Point of failure	Hub	Every node in the ring
Data traversal	All data passes through the central network connection.	Data moves in only one direction around the ring till it arrives the destination.
Network expansion	A new cable is plugged in from the new node to the hub.	In order to add a new node, a connection must be broken which turns down the network.
Fault isolation	Easy	Difficult
Troubleshooting	The other nodes are affected only in the case of a hub failure.	When a node goes down the information continues to transfer till the damaged node.
Cost	High	Low

Definition of Star Topology

Star Topology is the network architecture in which each device has a dedicated point-to-point link only to the central controller known as a hub. There is no direct link exists among the devices. It is dissimilar to mesh topology which allows direct traffic between the devices. In Star topology, the controller plays an important role and act as a mediator. When a device wants to send data to another, it first sends data to the controller which then relays the data to other connected devices.

Star topology needs only one link and I/O port to connect a device to another. That is the reason it is easy to install and reconfigure. The addition, deletion, replacement of the devices involves only one connection that is between that device and the hub. The cabling requirements are less in the star topology, but it is greater when we compare it with other topologies such as tree, ring and bus.

This topology is robust where even if the link fails, only that link is influenced and the other links remain active. It also makes fault identification and isolation easier. Hub observes link problems and bypasses faulty links.

Definition of Ring Topology

The Ring Topology connects each device with dedicated point-to-point line configuration to other two adjacent devices, and the first device connects to the last device. It passes a signal in only one direction from one device to other until it reaches the device sent the signal. A repeater is installed in each device in the ring. If a device receives a signal meant for another device, the device regenerates the bits and boosts the signal by using a repeater that is installed on each device and transfers them along. When the signal reaches the destination, the receiver sends back an acknowledgement to the sender.

Ring topology is easy to install and configure as each device is linked to its immediate neighbour. The addition, deletion and repositioning of a device just require changing only two connections. The only limitations are the traffic and media considerations, i.e., the maximum length of the ring and the number of devices.

The fault isolation in a ring can be simplified by using an alarm which alerts the network operator to the problem and its location. A signal is circulated continuously, if any device does not receive a signal within a specified time it can issue an alarm. Though, unidirectional nature of traffic can be disadvantageous for the network where even a single faulty cable can disable the entire network. This limitation can be overcome by employing a switch or a dual ring that is able to closing off the break.

Key Differences Between Star and Ring Topology

1. In the star topology, each device is connected to a central node which sends the information received from one device to the other and act as a mediator. On the other hand, in the ring topology, each device has two nodes connected to either side of it, and the last node is connected to the first one.
2. The star topology requires more cable than ring topology.
3. Hub in the star topology is considered as a point of failure because the failure of any device would not affect the whole network, but if hub goes down, no data is transmitted across it. In contrast, each node in the ring topology is considered to be a point of failure as the failure of any device could significantly affect whole ring network.
4. In a star topology, all the data travels through the central hub. As against, in the ring topology, the data passes through each node unidirectionally until it reaches the destination.
5. To add new nodes to the ring network, a cable is used to connect the new device to the hub without influencing the rest of the network. On the contrary, the addition of new devices is done by breaking a connection which results in temporary unserviceable network till the new device is activated.
6. Fault isolation is easier in star topology while it is quite difficult in the ring topology.
7. Troubleshooting in the ring topology is simple, as the information continues to transfer through the rest of ring until reaching the point of failure. Conversely, in the star topology, the other devices are affected only when the connecting device goes down [Hub].
8. Star topology is expensive than the ring because it requires central connecting device usually hub.

Conclusion

The star topology is used to connect primary-secondary type of connection whereas ring topology is used for peer-to-peer connections.