Network Topologies and their types

Network topologies refer to the arrangement and connection patterns of computers in the network. It is the physical layout of the terminal’s links and computers in the network. Network Topology can be defined as the cabling structure or geographical arrangement of computers in a local area is known as Network Topology or LAN Topology. Some topologies used in LAN are as follows.
1. Bus or Linear topology: It is the simplest network topology. In this type of topology, all the nodes (computers as well as servers) are connected to a single cable with the help of interface connectors. this central cable is the backbone of the network and is known as a Bus topology. It transmits the data from one end to another in a single direction. No bi-directional feature is in a bus topology.
In a bus topology, each computer communicates with another computer on the network independently. Every computer can share the network’s total bus capabilities. The devices share the responsibility for the flow of data from one point to the other in the network.
For Example Ethernet cable, etc.
Advantages of Bus Topology:

1. It is easy to set up and extends.
2. It is a comparatively cheaper and simple network.
3. The linear bus network is mostly used in small networks.
4. It is widely used when network installation is small, simple, or temporary.
5. Less cabling is required and Cost-efficient to implement.

Disadvantages of Bus Topology:

1. Efficiency is less when nodes are more(strength of signal decreases).
2. It is difficult to detect and troubleshoot faults at the individual station.
3. There is a maximum chance of collision of data.
4. If the main cable collapses, the complete network collapses.
5. Security issues and risks are more as messages are broadcasted to all nodes.

2. Star Topology: In this Topology, all the components of networks are connected to the central device(which may be a hub, a router, or a switch). The central device(hub or switch) has point to point communication link(the dedicated link between the devices which can not be accessed by some other computer) with the devices. The central device then broadcasts or unicasts the message based on the central device used. The hub broadcasts the message, while the switch unicasts the messages by maintaining a switch table. Broadcasting increases unnecessary data traffic in the network.
For Example High-Speed LAN, etc.
Advantages of Star Topology:

1. centralized management helps in monitoring the network.
2. failure of one node or link doesn’t affect the rest of the network.
3. In this topology, new nodes can be added easily without affecting the rest of the network.

Disadvantages of Star Topology:

1. If the central device(hub) fails, the entire network will fail.
2. performance as well as the number of nodes that can be added in such topology is dependent on the capacity of the central device.
3. The use of a hub, a router, or a switch as the central device increases the overall cost of the network.

3. Ring Topology: In Ring Topology, all the nodes are connected to each other in such a way that they make a closed circular loop. In this topology, a ring pattern is formed by connecting one computer to another and so on. There is no master computer to control data communication in a ring topology. There is no chance of data collision due to data traveling in only one direction i.e clockwise or anti-clockwise. It is an example of a peer-to-peer network mode.
TOKEN  is used for sending and receiving data in this topology. The token contains a piece of information along with data that is sent by the source computer. This token then passes to the next node, which checks if the signal is intended for it. If yes, it receives that signal and passes the empty into the network, otherwise passes the token along with the data to the next node. This process continues until the signal reaches its intended destination.
for Example Token Ring.

Advantages of Ring Topology :

1.  Each computer has equal access to resources.
2. Additional components do not affect the performance of the network.
3. This type of network topology is very organized so, it helps to reduce the chances of data collision.

Disadvantages of Ring Topology :

1. If one workstation or port goes down, the entire network gets affected.
2. The network is highly dependent on the wire which connects different components.
3. Each packet of data must pass through all the computers between the source and destination. So, makes it slower than a star topology.