WHAT IS A NETWORK TOPOLOGY?

Network Topology

- refers to the layout or structure of the network in relation with the flow of data. It is the way in which the elements such as computers, printers, servers, and other computing appliances are arranged in a network. In this instance, you take note not only of the device's location, but also how it is connected to the network, the type of cables in use, and its layout.

On the other hand, Logical Topology - depicts how information flows from one device to another within the network regardless of its physical design. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ between two networks, yet their topologies may be identical.

Types of Network Topologies

1.) Linear Bus Topology

- is a type of network topology in which each device is connected one after the other in a sequential chain (shown right). In this case, the bus is the network connection between the devices, and if any link in the network chain is severed, all network transmission is halted. It works well for small networks because it is simple to set up and utilizes shorter cables since each device is connected to the next. However, it is a poor solution for larger networks, as the entire network relies on each connection, and network speed is reduced as more devices are added.

Advantages of Linear Bus Topology

• Easy to connect a computer or peripheral to a linear bus.

• Requires less cable length than a star topology.

Disadvantages of Linear Bus Topology

• Entire network shuts down if there is a break in the main cable.

• Terminators are required at both ends of the backbone cable.

• Difficult to identify the problem if the entire network shuts down.
• Not meant to be used as a stand-alone solution.

2.) Star Topology

is a topology for a Local Area Network (LAN) in which all nodes are individually connected to a central connection point, like a hub or a switch. A star takes more cable than e.g. a bus, but the benefit is that if a cable fails, only one node will be brought down.

Advantages of Star Topology

•  As compared to Bus topology it gives far much better performance, signals don’t necessarily get transmitted to all the workstations. A sent signal reaches the intended destination after passing through no more than 3-4 devices and 2-3 links. Performance of the network is dependent on the capacity of central hub.
• Easy to connect new nodes or devices. In star topology new nodes can be added easily without affecting rest of the network. Similarly components can also be removed easily.
• Centralized management. It helps in monitoring the network.
• Failure of one node or link doesn’t affect the rest of network. At the same time its easy to detect the failure and troubleshoot it.

Disadvantages of Star Topology

• Too much dependency on central device has its own drawbacks. If it fails whole network goes down.
• The use of hub, a router or a switch as central device increases the overall cost of the network.
• Performance and as well number of nodes which can be added in such topology is depended on capacity of central device.

3.) Ring Topology

is a network configuration in which device connections create a circular data path. Each networked device is connected to two others, like points on a circle. Together, devices in a ring topology are referred to as a ring network.


In a ring network, packets of data travel from one device to the next until they reach their destination. Most ring topologies allow packets to travel only in one direction, called a unidirectional ring network. Others permit data to move in either direction, called bidirectional.

Advantages of Ring topology

• Reduced chances of data collision as each node release a data packet after receiving the token.
• Token passing makes ring topology perform better than bus topology under heavy traffic
• No need of server to control connectivity among the nodes
• Equal access to the resources

Disadvantages of Ring topology

In Unidirectional Ring, a data packet must pass through all the nodes.

Ex: Let’s say A, B, C, D, and E are a part of the ring network. The data flow is from A towards B and henceforth. In this condition, if E wants to send a packet to D, the packet must traverse the entire network to reach D.

Single point of failure, that means if a node goes down entire network goes down.

4.) Mesh Topology

A network setup where each computer and network device is interconnected with one another, allowing for most transmissions to be distributed even if one of the connections go down. It is a topology commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.

Advantages of a Mesh Topology

• Manages high amounts of traffic, because multiple devices can transmit data simultaneously.
• A failure of one device does not cause a break in the network or transmission of data.
• Adding additional devices does not disrupt data transmission between other devices.

Disadvantages of a Mesh Topology

• The cost to implement is higher than other network topologies, making it a less desirable option.
• Building and maintaining the topology is difficult and time consuming.
• The chance of redundant connections is high, which adds to the high costs and potential for reduced efficiency.

5.) Hybrid Topology

is a type of network topology that uses two or more differing network topologies. These topologies include a mix of bus topology, mesh topology, ring topology, star topology, and tree topology.

Types of Hybrid Network Topologies

There are different types of hybrid network topologies depending on the basic requirement of an organization but the most commonly used one is Star-Ring and Star-Bus topologies that make up the hybrid.

1. Star-Ring Network Topology
In a Star-Ring topology, a set of star topologies are connected with a ring topology as the adjoining topology. Joining each star topology to the ring topology is a wired connection.

Figure 1 demonstrates the Star-Ring topology:


Information from a given star topology reaching a connecting node in the main ring topology and the data can flow either in a bidirectional or unidirectional manner. A Uni-directional ring topology can transfer data in either clockwise or counterclockwise direction. thus, a uni-direction ring topology is a half-duplex, whereas a Bi-directional ring topology can transfer and receive data at the same time. Thus, a bidirectional ring topology can be called a full-duplex network.


2. Star-Bus Network Topology
A Star-Bus topology is the combination of star network topology and bus network topology, in Star-Bus network a set of star topologies are interconnected by a central bus network. Joining each star topology to the bus topology results the Star-Bus topology.

Figure 2 demonstrates the Star-Bus topology.

Advantages of Hybrid Topology

• Hybrid network combines the benefits of different types of topologies
• Can be modified as per requirement
• It is extremely flexible.
• It is very reliable.
• It is easily scalable

Disadvantages of Hybrid Topology

• It is expensive
• The design of a hybrid network is complex.
• Hardware changes are required in order to connect topology to another topology.

SOURCES:
D Whiz Computer 10 Book

Linear Bus Topology (https://www.computerhope.com/jargon/l/linear-bus-topology.htm#targetText=Linear%20bus%20topology%20is%20a,all%20network%20transmission%20is%20halted.)

Linear Bus Topology Advantages and Disadvantages (http://www.omnisecu.com/basic-networking/network-topologies-bus-topology.php)

Star Topology (http://www.telecomabc.com/s/star.html#targetText=A%20star%20topology%20is%20a,Star%20topology)

Star Topology Advantages and Disadvantages (https://www.ianswer4u.com/2011/05/star-topology-advantages-and.html)

Ring Topology (https://www.computerhope.com/jargon/r/ringtopo.htm#targetText=A%20ring%20topology%20is%20a,to%20as%20a%20ring%20network.)

Ring Topology Advantages and Disadvantages (https://fossbytes.com/what-is-ring-topology-advantages-and-disadvantages-of-ring-topology/#targetText=Reduced%20chances%20of%20data%20collision,Equal%20access%20to%20the%20resources)

Mesh Topology (https://www.computerhope.com/jargon/m/mesh.htm#targetText=A%20mesh%20topology%20can%20be,other%20computers%20in%20that%20network.)

Mesh Topology Advantages and Disadvantages (https://www.computerhope.com/jargon/m/mesh.htm)

Hybrid Topology 
(https://www.computerhope.com/jargon/h/hybrtopo.htm#targetText=A%20hybrid%20topology%20is%20a,star%20topology%2C%20and%20tree%20topology.)

Hybrid Topology Advantages and Disadvantages (https://computernetworktopology.com/hybrid-topology/)

Network Topology Picture (https://i.ytimg.com/vi/M4fnikdNQ28/maxresdefault.jpg)

Linear Bus Topology Picture (https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcUergPGHcUcwimQRA_CXPwTB31K79d-Dn3Aa9H8nw2hrrrjRPFIyd5M2m3sXJXPiB8ZmVgIoULTTCvxxo2FKaHSXgmVAvvU4u8E47I3472xbCnu9th806LjASsW6llGNwY3VUL4Y9Wg_Y/s1600/hi.png)

Star Topology Picture (https://fcit.usf.edu/network/chap5/pics/star.gif)

Ring Topology Picture (https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicSMSy_1LzoNKCpF5kCrhspY8h1VgwcnpBqQpxlGdxupxkAB5HJcay-NS8bpBFob1rzA-MRNzYSuO6UDAXcfF9TqUoiMea-ztgp11hVGbVwvCW6-Bkp3Ac5QMJauCMqKWRdIg4GSP1D5Sk/s1600/ringLAN.jpg)

Mesh Topology Picture (https://networksmania.files.wordpress.com/2012/03/mesh-topology1.jpg)

Hybrid Topology Picture https://i.pinimg.com/originals/e6/e2/79/e6e279ff1e390968fb889dc4c354c999.jpg)

take note: copy paste the link then click search if you want to know more info.