© Boardworks Ltd 20101 of 21

Introduction to Networks

© Boardworks Ltd 20102 of 21

Teacher’s notes included in the Notes Page

Flash activity. These activities are not editable. Web addresses

Icons key: For more detailed instructions, see the Getting Started presentation

Functional Skills check

Student task accompanies this slide Printable activity

The purpose and uses of networks.

The key components of a computer network.

The different types of network and the advantages and disadvantages of them.

This lesson will cover:

© Boardworks Ltd 20103 of 21

Networking is a way of connecting hardware together so that software, data, files and peripheral devices can be shared.

The importance of networks

Networksallow users to have access to lots of hardware devices from their personal terminal.

What other advantages do networks have?

© Boardworks Ltd 20104 of 21

10 Downing Street, London, England Sydney Opera

House, Australia

Jim’s Skateboards

USAPatel’s Fine Silks, India

The Internet

Koji Araki, Japan

The Internet is a network of networks that connects governments, people and companies all over the world.

What is the Internet?

© Boardworks Ltd 20105 of 21

The Internet began in the 1980s to allow US universities to share computer resources. It grew so much that by the 1990s it had become possible for people to use the Internet from home.

The World Wide Web (www) was developed to make browsing (viewing) easier through http (Hypertext Transfer Protocol).

http is a set of standards that allows web browsers and servers to communicate.

Where did it begin?

© Boardworks Ltd 20106 of 21

Network components – modems

A modem stands for modulator–demodulator. They connect computers to the Internet or distant networks by converting the digital, binary signals into an analogue signalthat can be transmitted down telephone lines.

Old modems converted digital information to an audio signal. Press play to hear this.

Modern modems are built into computers and use DSL or ADSL technology. These use much higher transmission frequencies which allows for faster data transfer.

© Boardworks Ltd 20107 of 21

In order for a computer to function as part of a network, it has to have a special piece of equipment installed to give it this capability.

Network components – network cards

This is called a Network Interface Card or NIC. It has a port for a network cable to be connected.

NICs are still very common,but increasingly people areusing wireless network cardsor wireless USB adaptors.

© Boardworks Ltd 20108 of 21

Ethernet is the name given to the most common method of networking computers. Although other methods exist, Ethernet has been the standard since the 1990s.

Ethernet and alternatives

Ethernet uses Cat5 cables to connect computers together.

What alternatives are there to Ethernet?

© Boardworks Ltd 20109 of 21

There are many types of network cable.

Twisted-pair cables are the most common. This cabling is often called ethernet cabling. Category 5 (Cat5) twisted-pair cables can carry 100 Mb per second over distances of up to 100 metres.

Coaxial cable is better at resisting interference and can be run for longer lengths, but it is not as flexible and is not used much now.

Fibre optic cable can transfer data at higher speeds over longer distances, and can be used outside buildings, but it is much more expensive. It has a central core made of glass and transmits the signals using light.

Cables

© Boardworks Ltd 201010 of 21

Remember the terminology

© Boardworks Ltd 201011 of 21

Hubs, switches and routers

© Boardworks Ltd 201012 of 21

Wireless networks

With improvements in radio technology, it has become possibleto connect computers on a LAN network without using wires.

A wireless network card is similar to a standard NIC, but has atransmitter/receiver forsending signals via radio waves.

Wireless networks arepopular as they allow theuser more freedom, such as working outdoors.

Are there any problems with wireless networks?

© Boardworks Ltd 201013 of 21

Wi-Fi hotspots

Wi-Fi technology allows users to wirelessly connect to the Internet. Access points are set up at various locations from which users can connect to a wireless networkand access the Internet.

Many cafes and bars offer wireless hotspots, allowing users to work where they please.

What benefits and drawbacks might establishments face when offering Wi-Fi access?

© Boardworks Ltd 201014 of 21

Benefits and drawbacks

© Boardworks Ltd 201015 of 21

Mobile networks

It is now incredibly common to use mobile devices to access a network. Most modern mobiles allow Internet access via 3G (third generation) networks.

It’s not just mobiles though. Tablet computers, PDAs, E-readers and even gaming devices like the Nintendo DS are all being created with the ability to connect to local area networks (LANs) or wide area networks (WANs) without the need for cables.

© Boardworks Ltd 201016 of 21

Each computer on a network has to have a network address so that the data knows where it is being sent.

Computers connected to the Internet have their own IP address to allow data packets to arrive at the right location.

IP192.168.10.2

Packets

Computers break down data into small parts so they can find the quickest route to their destination. These small parts are called packets and will be reassembled when they arrive at the right destination.

© Boardworks Ltd 201017 of 21

The domain name system links the IP address (e.g. 217.27.240.45) with the text name or web address (e.g. http://www.boardworks.co.uk). This means that users only have to remember a short name instead of lots of numbers.

Most people still refer to this as a website address but its proper name is a URL or UniformResource Locator.

URLs

© Boardworks Ltd 201018 of 21

When you are deciding whether the information from a website is reliable, take a look at the URL. It will give you some idea about the source of the information.

www, standing for World Wide Weban organization name (.boardworks)a top level domain (.co)a country (.uk).

URLs are usually made up of these parts:

There are many top level domains, for instance .com, .org (organization), .sch (school) and .ac (university).

URLs

© Boardworks Ltd 201019 of 21

To allow different types of computers in different parts of the world to interact, there has to be some agreement about how they communicate.

These standards are called protocols.

http is the first part of many web addresses – it stands for hypertext transfer protocol, and states the protocol that the site will use to communicate.

HTML stands for Hypertext Markup Language, and it is the standard language for writing web pages.

Speaking the same language

What does HTTPS stand for?

© Boardworks Ltd 201020 of 21

Acronyms

© Boardworks Ltd 201021 of 21

True or false?