NETWORKS

Stand Alone

Computers can be used on their own without being connected to a network but all computers now have the capability to connect with a network.

Local Area Network

A Local Area Network ( LAN) is a small network in a single room, building or site. Examples are:A school networkA network in an office Connecting computers together to play

games at home. The computers can be linked using

copper cables or by a wireless connection.

WiringName Description

Twisted Pair This cable consists of two copper wires twisted around each other.Widely used because it is cheap and capable of transmitting data at speeds of 100 Mbps

Coaxial Not so commonly used as it is more expensive. It is used where there is lots of interference that can corrupt data because it has a protective shield to prevent interference.

Fibre-Optic Fibre - Optic cable is made up of fine strands of glass that transmit data as pulses of light. Fibre optic cable transmits at very high speeds. It doesn’t loose data because of interference and is very secure. It is very expensive to install.

Wireless

Wireless networks use radio waves, microwaves or infrared light to transmit data.

All you need is a transmitter / receiver in every machine and a central device, such as a wireless router; to pass the data around the network.

Advantages to wireless

Wireless networks are easy to install, as there is no need for cables.

You can move around when you work. Reasonably fast transmission speeds

( though slower compared to physical cables)

Disadvantages to wireless Very vulnerable to hackers who can ‘tap

in’ to signals. Care is needed when setting up network

security if you don’t want other to access your files or use your internet connection.

The Internet The Internet is a global system of interconnected computer

networks.

It has a number of different elements:

The World Wide Web which is made up of multimedia web pages that are stored on computers across the world. Web pages hold text, sound, graphics, animations and videos. These are linked by hyperlinks.

Search engines to help users find their way around the internet.

Forums and chatrooms where you can meet people and discuss all sorts of topics.

What is cloud storage?

Video

Local Vs Cloud

Businesses now have the choice of buying and installing their own computer hardware and software, and paying for network connections, maintenance and updating, or they can use the ‘Cloud’.

This means they can rent equipment, software, storage facilities and access to the internet on a pay – as – you –go basis.

Cloud Customers Local / non-Cloud users

Do not own the physical infrastructure, they are owned by the Cloud Computing provider.

Own their own computer, backing storage and wired or wireless connection equipment.

Can rent storage space on servers.Customer can have a contract that enables them to decide how much storage space they need for their data.This arrangement can be flexible and scaled.

Own their own hard drives, optical storage and servers, which they have to maintains and update.

Can have access to powerful networks without great initial expense.A business does not need to spend a large amounts of money buying and installing systems.

Must bear the initial costs in buying computers, backing storage and software, which can be very high.

Can access a wide range of application software and software for developing applications without paying or installing.

Need to pay for and install all the software required.

Have access to technical support, which is standard to the service.

Need to provide/ pay for technical support.

Are billed for their service based on either time they spend using the network or on a monthly or quarterly basis. It is flexible.

Must bear the high initial setup costs before the business can begin to use the system.

May have what is called a hybrid cloud system where important data is stored locally. Security concerns mean that some customers keep what is called ‘mission critical data’ in computer storage.

Are responsible for their own security. They do not have the worry that data stored on the ‘Cloud’ can be hacked.

Client/ServerClient/Server Clients are workstations Servers are central computers Servers have:

powerful processorsLarge memory capacity

Clients are workstations Servers are central computers Servers have:

powerful processorsLarge memory capacity

<- NICs Ex2 ->

Client/Server

The servers provide the resources for the computers { clients} connected to the network for example:

Printer servers File Server Proxy server

Client/Server

In a client server network it is possible to :organise Security for the whole networkorganise Backups for all the data on the

networkcontrol who can access the network by setting

up accounts {with IDs and passwords}

Peer to Peer network In a peer to peer network there is no

central server. The computers are linked together to

enable them to send and receive data. Each computer must back up its own data

and organise its own security

Peer to Peer Network

Peer to Peer network

Since there is no centrally organised security of backup system on a Peer to Peer network:

They are only suitable for ‘trusting’ environments’ e.g. home use.

They are not suited to commercial or business use.