A topology is the geometric representation of the relationship exist between the links and linking devices (nodes) to each other. 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
|Basis for comparison||Star Topology||Ring Topology|
|Architecture structure||Peripheral nodes are connected 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 travels in only one direction around the ring until it reaches 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.|
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 between 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 affected and the other links remain active. It also makes fault identification and isolation easier. Hub is used to monitor link problems and bypass defective 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. Every device in the ring incorporates a repeater. If a device receives a signal intended for another device, the device regenerates the bits and boosts the signal by using a repeater that is installed on each device and passes them along. When the signal reaches the destination, the receiver sends back an acknowledgement to the sender.
Ring topology is easy to install and reconfigure 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 using a dual ring or a switch capable of closing off the break.
Key Differences Between Star and Ring Topology
- 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.
- The star topology requires more cable than ring topology.
- 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.
- In a star topology, all the data passes through the central hub. As against, in the ring topology, the data passes through each node unidirectionally until it reaches the destination.
- 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.
- Fault isolation is easier in star topology while it is quite difficult in the ring topology.
- 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).
- Star topology is expensive than the ring because it requires central connecting device usually hub.
The star topology is used to connect primary-secondary type of connection whereas ring topology is used for peer-to-peer connections.