# Different network topologies submitted by Atif Baloch . Roll no 1103-BH-GEOG-2018. SECTION G1 . SUBMITTED TO sir imran

Name Atif baloch
Roll no. 1103-BH-GEOG-2018
Section. G1
Topic. Different network topologies and why we use them
Submitted to. Sir Imran
Subject. C.A

What is topology?
Network topology refers to the physical or logical layout of a network. It defines the way different nodes are placed and interconnected with each other. Alternately, network topology may describe how the data is transferred between these nodes. Network Topology refers to the layout of a network and how different nodes in a network are connected to each other and how they communicate. Topologies are either physical the physical layout of devices on a network or logical the way that the signals act on the network media, or the way that the data passes through the network from one device to the next. There are two types of network topologies: physical and logical. Physical topology emphasizes the physical layout of the connected devices and nodes, while the logical topology focuses on the pattern of data transfer between network nodes. The physical and logical network topologies of a network do not necessarily have to be identical. Different network topologies are as follows :
Mesh Topology
In a mesh network, devices are connected with many redundant interconnections between network nodes. In a true mesh topology every node has a connection to every other node in the network.
A mesh topology is a point-to-point connection where nodes are interconnected. In this form of topology, data is transmitted via two methods routing and flooding. Routing is where nodes use routing logic to work out the shortest distance to the packet’s destination. In contrast flooding, data is sent to all nodes within the network. Flooding doesn’t require any form of routing logic to work.
There are two types of mesh topologies:

Full mesh topology
Full mesh topology occurs occurs when every node has a circuit connecting it to every other node in a network. Full mesh is very expensive to implement but yields the greatest amount of redundancy, so in the event that one of those nodes fails, network traffic can be directed to any of the other nodes. Full mesh is usually reserved for backbone networks.

Partial mesh topology
Partial mesh topolgy is less expensive to implement and yields less redundancy than full mesh topology. With partial mesh, some nodes are organized in a full mesh scheme but others are only connected to one or two in the network. Partial mesh topology is commonly found in peripheral networks connected to a full meshed backbone.

Star Topology
In a star network devices are connected to a central computer, called a hub. Nodes communicate across the network by passing data through the hub.

Main Advantage: In a star network, one malfunctioning node doesn’t affect the rest of the network.

Main Disadvantage: If the central computer fails, the entire network becomes unusable.

Bus Topology
In networking a bus is the central cable the main wire that connects all devices on a local-area network (LAN). It is also called the backbone. This is often used to describe the main network connections composing the Internet. Bus networks are relatively inexpensive and easy to install for small networks. Ethernet system uses bus topology. Bus topology is a type of network where every device is connected to a single cable which runs from one end of the network to the other. This type of type of topology is often referred to as line topology .In a bus topology, data is transmitted in one direction only

Main Advantage: It’s easy to connect a computer or device and typically it requires less cable than a star topology.

Main Disadvantage: The entire network shuts down if there is a break in the main wire and it can be difficult to identify the problem if the network shuts down.

Ring topology:

Ring topology is a local-area network (LAN) whose topology is a ring. That is, all of the nodes are connected in a closed loop. Messages travel around the ring, with each node reading those messages addressed to it.
In networks with a ring topology, computers are connected to each other in a circular format. Every device in the network will have two neighbors and no more or no less. The first node is connected to the last node to link the loop together. As a consequence of being laid out in this format packets need to travel through all nodes on the way to their destination.
Main Advantage: One main advantage to a ring network is that it can span larger distances than other types of networks, such as bus networks, because each node regenerates messages as they pass through it.
Tree Topology:
This is a “hybrid” topology that combines characteristics of linear bus and star topologies. In a tree network, groups of star-configured networks are connected to a linear bus backbone cable.

Main Advantage: A Tree topology is a good choice for large computer networks as the tree topology “divides” the whole network into parts that are more easily manageable.

Why we use different network topologies ?
In this technological world world, networking plays a crucial role in every individual’s and every organization’s day-to-day activities. But there has to be some specific models or guidelines that must be followed to connect one device to another. This logical or physical layout or configuration of a network is known as a network topology, and if you are an IT pro, here’s what you need to know.
A network topology is a substantial arrangement of a network in which all the nodes are connected with each other using network links or connecting lines. Apart from just describing how the nodes are interconnected, network topology also explains how the data is transferred in a network.
A logical network topology is a high-level representation of how two or more nodes are connected. A logical network topology describes or explains how signals act on a network and how the data is transmitted from one node to another at a very high level. On the other hand, a physical topology describes how nodes are physically connected to each other. The physical connection can be made using wires, wireless connectivity, networking components, and more.
We can think of topology as the virtual shape or structure of the network. Network topology is also referred to as ‘network architecture.
Devices on the network are referred to as ‘nodes.’ The most common nodes are computers and peripheral devices. Network topology is illustrated by showing these nodes and their connections using cables. There are a number of different types of network topologies, including point-to-point, bus, star, ring, mesh, tree and hybrid.
Point-to-point topology
It is the simplest of all the network topologies. The network consists of a direct link between two computers. This is faster and more reliable than other types of connections since there is a direct connection. The disadvantage is that it can only be used for small areas where computers are in close proximity.
It connects two nodes directly together with a common link. The entire bandwidth of the common link is reserved for transmission between those two nodes. The point-to-point connections use an actual length of wire or cable to connect the two ends, but other options, such as satellite links, or microwave are also possible.
When you change TV channels by remote, you are establishing a point to point connection between the remote control and the TV’s control system.
The transfer of data in a point to point topology can be in multiple ways across the network: in a simplex, in full duplex, or half duplex.

Importance of topology
 Plays a significant role in the functioning of networks.
 Helps us better understand the networking concepts.
 Plays a crucial role in performance.
 Helps reduce the operational and maintenance costs such as cabling costs.
 A network topology is a factor in determining the media type to be used to cable a network.
 Error or fault detection is made easy using network topologies.
 Effective utilization of resources and networking components

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