This video explains the topologies in computer networks.
A topology is a layout of a computer network. There are two types of topology: physical and logical.
A physical topology defines how devices on the network are connected.
A logical topology describes how data flows over the physical topology. Based on its layout, we can further classify a topology into Bus, Star, Ring, Mesh, and Point-to-Point. Each subtype arranges devices or moves data differently from others.
Bus
A bus topology is the earliest implementation of computer networks. By far, it is the most simple and oldest topology. It arranges all nodes in a line. A node is a network device. Computers, printers, and servers are examples of nodes. It uses a bus for physical and logical layouts.
This topology has the following advantages.
It uses the most straightforward layout.
It requires minimal components to set up.
It is easy to implement and maintain.
It has the following disadvantages.
It is outdated and no longer used in modern networks.
It provides the slowest speed among all other topologies.
A break in cable or an open connection can bring the entire network down.
Ring topology
A ring topology uses a multi-access unit at the centre of the network. All nodes connect to it, forming a star-like layout. A star-like layout is called a star topology.
Although it uses a star topology for physical layout or cabling, it does not use the same design for data transportation. Electrically, this network behaves like a ring, where signals travel around the ring to each node.
It uses a token-passing method to eliminate all possibilities of collision in the network.
Advantages
It has the following advantages.
It is a collision-free topology.
It uses a simple physical layout.
It requires less hardware.
Disadvantages
It has the following disadvantages.
Nodes can not communicate directly.
It provides slow data transfer speed.
It is a less secure topology.
Star topology
A star topology uses a physical layout similar to the ring topology. However, there is a difference. It uses a hub or ethernet switch to connect nodes. The data flow on this topology depends on what it uses to connect nodes. If it uses a hub, the data flows in a bus layout. If it uses an ethernet switch, data flows in a bus or point-to-point layout.
Advantages
It is a collision-free topology.
It provides a faster data transfer speed.
A cable break has limited effects.
Since it is a collision-free topology, it provides a faster data transfer speed than other topologies.
Disadvantages
It is tough to implement and troubleshoot.
Only network administrators can manage it.
It requires more hardware resources.
It is more expensive than other topologies.
Point-to-point topology
A point-to-point topology connects only two devices. It does not require any intermediate device. Devices can use any supported cable type for the connection. For example, they can use a cross-over ethernet cable or wireless signals. Since there are no third devices, they do not face any collision. If we talk about the logical implementation, it is a bus topology.
Point-to-multipoint topology
A point-to-multipoint topology connects a single device to many devices. It is mainly used in WAN networks. It connects one central or main branch with sub-branches. Physically, it is a point-to-multipoint layout. Logically, it is a point-to-point topology. It does not fulfil the requirement of a logical bus topology. Data sent by one device does not reach all remaining devices. Devices also do not share the same collision. It is similar to a switch-based star topology where if the switch knows the destination address, the source and destination nodes use a logically point-to-point connection to exchange data.
FDDI Ring topology
It connects all devices in a ring. It uses optical fibre cables to connect devices. It connects the first device to the second, the second to the third, and so on. It connects the last device back to the first device, making a physical ring layout.
Mesh topology
A mesh topology creates multiple connections between devices. There are two types of mesh: full and partial. A full mesh connects every device with all other devices in the network. A partial mesh connects a device only with the necessary devices. Both use point-to-point topology for data transportation.
Hybrid topology
A hybrid topology connects two different topologies. It was mainly used during the transition period when networks were migrating from the coaxial cable-based bus topology to the hub-based star topology. It uses a bus topology for data transportation.
At that time, hubs with a coaxial port were available. It allowed administrators to use the hub-based star topology to build new networks while maintaining connectivity with existing coaxial cable-based networks.
This topology is no longer used in modern networks.