1.4 wired and wireless networks lesson 1

The Big Picture: Wired and wireless networks Types of networks: LAN (local area network) & WAN (wide area network) The different roles of computers in a client-server and a peer-to-peer network Factors that affect the performance of networks Network topologies The hardware needed to connect stand-alone computers into a local area network: Wireless access points Routers/switches NIC (network interface controller/card) Transmission media The internet as a worldwide collection of computer networks: DNS (domain name server) Hosting The cloud The concept of virtual networks

Thought for the day - Networks What is the biggest network that we use? How many networks do you think you use in a day? How many have you used today?

Introduction to networks Consider this: Why do we think it is a good idea to network computers together? What did we hope to gain from networking computers together? Watch video: https://www.youtube.com/watch?v=oaNfeClDMu0

Learning Objectives By the end of today’s lesson, you will: Understand why we network computers together Be able to describe what is meant by a LAN Be able to describe what is meant by a WAN Understand what is meant by a client-server network Understand what is meant by a peer-to-peer network

Starter What is the biggest network that we use? How many networks do you think you use in a day? How many have you used today?

Thinking about networks Identify 5 daily activities that you use a network for Could you carry our these activities without the use of a network. Are there any activities that you cannot do, or would need to change without the use of a network?

What is a computer network? Two or more computers connected together to share information and resources. This could be a wired network using physical cables or wireless connections, or both

Benefit 1 – Sharing resources Benefits of a network Benefit 1 – Sharing resources Sharing an Internet connection Sharing folders and files so you can access your own documents and shared documents from any computer on the network Sharing software (legally) Sharing peripheral devices such as printers and scanners

Benefit 2 - Communication Benefits of a network Benefit 2 - Communication Using email to communicate with colleagues Transferring files between computers Using messaging systems/video calls to hold remote meetings, conference calls, to talk online using VOIP

Benefit 3 – Centralised Management Benefits of a network Benefit 3 – Centralised Management Centralised backup of all files Users can use any PC on the network but still see their own files Software can be distributed across the network rather than having to install it on each computer User profiles and security can be managed centrally Security can be set up across the network eg user access, firewalls, virus checking etc

Possible issues with a network Security – need to be vigilant in protecting data, setting appropriate access policies, and maintaining high standard of security Expertise is needed to create and maintain them Issues when the network “goes down” Reliance on internet

Ways to describe a network There are several ways to describe a network of computers: The relationship between the computers that make up the network The geographic area the network covers Topology – the layout of the computers

Client Server vs Peer-Peer There are two ways of setting up a network to share data and services where computers have different relationships with each other Client Server Peer-Peer The network relies on a central server All clients (devices) request services from the server (e.g. print services / file services) Additional hardware would be needed e.g. high end powerful servers Client computers are a lower spec than the server Servers can be specialised eg printer server, email server Server can be a computer or the software All computers have equal status Each device can act as a client and a server All devices can request and provide network services No additional hardware / software needed to set up this type of network so are easy to set up

Client Server vs Peer-Peer

Client Server vs Peer-Peer File/Software Storage All files can be stored centrally on a Client-server Workers can access files from any computer All computers can update central databases On Peer-Peer all files are stored on their own computers Users have to log-in to the same computer every time to acces their files

Client Server vs Peer-Peer File/Network Back-up Backups are easily managed on a Client-Server as these can be done centrally from the File Server All data is backed up in one go Individual computers do not need to be backed up With Peer-Peer all computers are responsible for backing up their own files

Client Server vs Peer-Peer Network security Centralised security on Client-Server – antivirus and firewall can be installed and configured from a central location Peer-Peer – individual security may need to be installed on individual machines, so may not be consistent. Also, direct file sharing, whilst a useful feature, has led to much illegal file sharing online

Client Server vs Peer-Peer Amount of network traffic Peer-Peer is appropriate for a small number of computers and a low traffic environment. Can become unpredictable and slow Client-server is useful for if there are lots of computers and it will be a high traffic environment.

Show your understanding Complete the worksheet by ticking the correct box(es) to show whether the statements apply to a client-server, a peer-to-peer or both networks Wired and Wireless Networks_L1_P2P_CS.docx

LAN vs WAN Networks can also be described by the geographic area they cover. There are 2 main LAN (Local area network) WAN (Wide area network) And also PAN (Personal area network)

LAN vs WAN LAN (Local area network) Computers are connected together over a small geographical area such as a single building or a single site LAN has its own infrastructure of cabling and network hardware due to distance and practicalities E.gs of LANs Home network School network Network in a shop

LAN vs WAN WAN (Wide area network) Computers are connected over a large geographical area. This could be several buildings/sites, town wide, county wide or even country wide. WAN uses external hardware and external infrastructure e.g. use of satellite, phone lines or The Internet, provided by a telecoms company The biggest WAN would be a global collection of networks (known as The Internet)

Other geographic networks PAN - Personal Area Network Personal devices are connected, often in the home Transmission over a short distance (10m) by devices such as laptops, phones, tablets, media players, speakers, printers Bluetooth could be used as well as wi-fi/cables MAN – Metropolitan Area Network Devices are connected in a city Less common now that it used to be due to the widespread availability of fast mobile data using 4G VPN - Virtual Private Network: will come back to this!

Show your understanding Complete the worksheet by filling in the characteristics and functions of a LAN and a WAN: >Log into Moodle>Go to ICT & Computing>GCSE Computer Science 2016-18>Computer Systems> 1.4 – Wired and Wireless Networks > iBytes 1.4.1 14. Wired and Wireless Networks_L1_LAN_WAN_PAN.docx You may need to do some further research to complete the sheet

Plenary: Key Words Define: Network LAN WAN PAN Client-server Peer-to-peer