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Table Of Content

1. Introduction
2. Clients and Servers
3. IP Addresses
4. Network Hubs and Switches
5. Routers and Firewalls


Introduction to networking

This document covers basic fundamentals of how networking works, approaches to use different devices to develop networks. Computer networking has been in existence for many years, and since time has passed the technologies are getting to be faster and less costly. Networks contain various devices—computers, switches, routers—connected together by cables or wireless signals. Understanding the basic principles of how networks constructed is an important help building a wireless network within a community or neighborhood.

This module covers the concepts of:

Clients and Servers

how services for instance e-mail and webpages connect using networks.
IP addresses—how devices over a network are available.
Network hubs, switches and cables—the hardware play blocks of any network.
Routers and firewalls—how to prepare and control the flow of traffic using a network.
Reading through these components should take between 30 minutes to an hour. Exploring the activities and specifics of the subject using a group will need longer.

An important relationship:

on networks is the one about the server as well as the client. A server is usually a computer that holds content and services for instance a website, a media file, or even a chat application. A good example of a server could be the computer keep website for Google’s search page. The server holds that page, and sends out when requested.

A client is usually:

a different computer, including your laptop or cellphone, that requests to see, download, or make use of the content. The client can connect spanning a network to change information. For instance, whenever you request Google’s search page using your web browser, your computer would be the client.

In the example below:

two computers are connected as well as an Ethernet cable. These computers is able to see each other and communicate on the cable. The client computer requests a website through the server computer. The website is delivered on the server, and displayed on the client’s internet browser.

IP Addresses

In order to send and direct data across a network, computers have to be able to identify destinations and origins. This identification can be an IP—Internet Protocol—address. An IP address merely set of four numbers between 1 and 254, separated by dots. An example of an IP address is

An IP address:

An IP address is comparable to a street address. Parts of the address describe wherein the world the structure is located, another part narrows it to a state or city, then your area within that state or city, then this location at work.

Below we could see 192.168.1 Street. On it are three houses:

The complete addresses for every of these houses is:,, and

There will vary classifications:

There will vary classifications, or sorts of IP addresses. A network could be public, or it could be private. Public IP addresses can be found anywhere on the Internet. Private IP addresses will not be, and quite a few are typically hidden behind a machine with a public IP address.


Here you can see an example:

a street with two buildings with public IP addresses—representing computers with addresses which can be visible for the entire Internet. These buildings could be anywhere in the entire world, however addresses are complete, and we know exactly where they’re and can send messages directly to them.

To see an illustration:

To see an illustration of how public and private IP addresses are generally used, let’s take another look at 192.168.1 Street. We have a new building at work. That building carries a public IP address, plus a private IP address. There is also a fence that blocks the remainder of the Internet from seeing and passing messages to addresses in the pub.

The postal building:

The postal building controls messages that travel between Internet and also the street, monitoring messages that leave the highway, and directs return messages for the right house. On the path, they have the address, additionally, on the Internet it’s the address

Network Hubs and Switches

Traditionally, computers are linked with each other using cables—creating a network. The cable used generally is Ethernet, which consists of four pairs of wires within a plastic jacket. It is physically a lot like phone cables, but they can transport considerably more data.

But cables and computers alone tend not to make a good network, so one early solution ended up being use a network hub. The Ethernet cables on the computer get connected to the device comparable to the hub of any bike wheel—where each of the spokes add up in the center.

An illustration showing:

An illustration showing how a hub works is shown below. Computer A would like to send a note to computer B. It sends what it’s all about through the Ethernet cable towards the hub, then a hub repeats the material to the many connected computers.

A network employing:

A network employing a hub can decelerate if many computers are sending messages, simply because they may make an effort to send messages simultaneously and confuse the hub. To help on this problem, networks started use another device known as a switch. Instead of repeating all messages which come in, a switch only sends what it’s all about to the intended destination. This eliminates the unnecessary repetition in the hub.

Using a switch, computer A sends a communication to computer B—the other computers will not see the material. Those computers can send other messages as well without interfering.

Switches have a limitation:

Switches have a limitation though—they only know in regards to the addresses of exercise machines that is plugged right into them. So, you may only send messages to your small number of devices—however many ports the switch has! If you need to send a note to a computer on another network, it will need to become sent by having a router, which we discuss next.

Routers and Firewalls

Routers perform the majority of the efforts on a network – they’ve created the decisions about all of the messages that travel around the network, and getting in touch with pass messages back and forth outside networks. There are three main functions:

Separate and Bridge:

Routers separate networks into sections, or bridge different networks together, as we see within the example above—the private network of 192.168.1 Street is bridged to the Internet which has a public IP address.

Assign IPs:

They can assign IP addresses. In the illustration of 192.168.1 Street, in case a new house is constructed on the street, it might get no matter the next highest house number available. In the case of routers, they assign IP addresses using DHCP—Dynamic Host Configuration Protocol.

Firewall and Protect:

They can filter messages or keep users away from private networks. Most routers employ a Firewall built-in. This is a software function that keeps unwanted messages from reaching the computers with this report, or private part, with the network.