What is a Network? | Need | Components | Types

What is a Network

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Let us consider a scenario. You want to send an email to your friend. So, what will you do? You will just open the Outlook, Gmail or whichever app you use, type his/her email address, write your content and hit send.

But, do you know how things work in the background? No, right? The reason you are able to send the email is the presence of Network. So, before going to see what the network actually is, we will see its need.

Need for Networking

Just like the example of email communication, one can watch the live streaming videos, or play online games because of networking.

How? well, let us consider that you are watching a YouTube video on your personal computer.

Now, that video must be stored somewhere, right? and how come you are able to watch something stored somewhere else rather than on your PC? The answer is Networking.

What is a Network?

A network can be said as the interconnection system of two or more devices which can share the data.

what is a network
Network Example

The sharing of the data is called as communication and for this communication to happen smoothly and securely, the network follows some protocols.

After reading this, you might have one doubt in your mind? Why protocols?

Consider the example of file sharing. Suppose you are using a Samsung phone to send the file to your friend. He/She might be using iPhone by Apple.

Now as both the vendors are different, the communication still works fine. It is because of the protocols both the vendors agreed upon.

The protocols are to identify the devices and make connections as well as to specify how the data should flow and what should be allowed and what should not.

There are two models for vendors to follow while generating the protocols.

  • OSI Reference model
  • TCP/IP model

We will see these reference models and protocols in separate posts in details.

Components of a Network

You are wondering by seeing the image above that how two PC’s are connected only. Well, that’s just a basic example. In reality, there are at least hundreds of thousands of devices connected with each other globally.

From your local computer to the computer of your friend sitting in South Africa, there are multiple devices connected.

Let us just see the components one by one.

Hub

The dumb device. Dumb? how a device can be dumb?

The hub has ports where the hosts (PCs for example) are connected. The hub just receives the signal from one of the hosts and broadcasts (sends to all) it to every other host via its ports. This is why the hub is considered as a dumb device.

Hub is used to form small network. It is a OSI layer 1 device.

Switch

The better and little bit expensive alternative to the hub. Just like the hub, the switch also contains multiple ports. It connects multiple hosts to form a network (local).

The switch has mac address (physical address of a device) table. So, it can identify the devices connected and thus avoid unnecessary traffic. It just forwards the data from source host to the destination host without any communication with the other hosts unless necessary.

Router

A router is to connect multiple local area networks (which are built using switches). It is to route the packets from one local network to another. It is a OSI layer 3 device.

It has routing table which contains IP adresses (logical address) of the hosts.

It can filter the network traffic using network ids or IP address along with the protocols (using ACL).

Types of Network

Following are the three types of networking.

Local Area Network (LAN)

This type of network is formed when the devices in very close area are connected together to form a network. LAN is able to deliver high speed of data transfer in low cost.

Examples: A classroom, a building

LAN consists of switch and host devices (PCs, Printers, etc).

Metropolitan Area Network (MAN)

Wider than LAN, Metropolitan Area Network does consists of the network across an entire city. It can cover the area up to several miles. Connects multiple LANs which are in just 10s of miles of distance.

Wide Area Network (WAN)

Wide Area Network is formed using a combination of multiple LANs. This is to connect LANs which are at a large distance. Router is the primary device to build a WAN.

In the next articles, we are going to see the cables which are used to connect devices, OSI and TCP/IP models, protocols like TCP, UDP, Routing and more in separate posts.

Also Read: How To Install Virtual Box On Windows

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