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Networks

. What is a network?. Networks. Standard Grade Computing Studies. Stand Alone or Networked?. A stand alone computer is one that is not connected to a network This could be a desktop computer or a laptop that has no wired or wireless connection.

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Networks

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  1. . What is a network? Networks Standard Grade Computing Studies

  2. Stand Alone or Networked? • A stand alone computer is one that is not connected to a network • This could be a desktop computer or a laptop that has no wired or wireless connection.

  3. A series of computers linked together so that they can send and receive data. We use them for sending e-mails, downloading files, shopping, etc You need to know about Local Area Network (LAN) The Internet <- What is a network? Local Area Networks -> What is a Network?

  4. <- LANs LAN Advantages -> Local Area Network (LAN) • Cover a small area such as one room or building. • Our school has a LAN • Each computer on a LAN is called a station • One station is called the file server. • The file server is where all the data & files are kept

  5. <- LAN Advantages Ex 1 -> Advantages of a LAN • Share data e.g. files in Our school folder • Share devices attached to the network (like a printer) • E-mail • Security ..Passwords ..Different levels of access • You can log onto any station connected to the LAN

  6. <- LAN Advantages Transmission meda -> • What is a LAN? • 2 Describe your school’s LAN • 3. Write down 3 advantages of a LAN Exercise 1

  7. <- Ex1 Wireless -> Transmission media for LAN • Stations can be connected by cables or wireless technology Cables: Coaxial cables Twisted-pair Cabling Optical fibre Uses light beams to transmit data at High speeds Expensive but doesn't get interference

  8. Fibre Optic Cable • High speeds: • Uses light beams to transmit data at High speeds { 100 terabytes per second is possible} • Doesn’t get interference { unlike copper wire cable} • More secure: • Difficult to intercept data on a fibre optic cable • Expensive to install

  9. Wireless Infrared communication Used for wireless mouse and keyboard Bluetooth Range of about 10 metres WIFI(Wireless Fidelity Alliance) Range of about 12-50 metres Bluetooth & WIFI use radio waves <- Transmission media NICs -> Transmission media for LAN

  10. <- Client/Server WANs -> Exercise 2 1. Name 2 types of cable used in a network. 2. What type of cable does the school have on its LAN? 3. How can you link up the computers at home without using cables?

  11. <- NICs Ex2 -> Client/Server • Clients are workstations • Servers are central computers • Servers have: • powerful processors • Large memory capacity

  12. Client/Server • The servers provide the resources for the computers { clients} connected to the network for example: • Printer servers • File Server • Proxy server

  13. Client/Server • In a client server network it is possible to : • organise Security for the whole network • organise Backups for all the data on the network • control who can access the network by setting up accounts {with IDs and passwords}

  14. 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

  15. Peer to Peer Network

  16. 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.

  17. <- Ex5 Modems and Dialup -> The Internet • A network of networks • Can be accessed by any internet-ready computer system. • You need: • A telecommunications connection such as a modem or broadband • A browser • A link to an Internet Service Provider

  18. <- WANs Ex3 -> Transmission Media for The Internet • The Internet uses Telecommunications links • It communicates information around the world using: • Microwave transmission • Satellite links • Optical Fibre • Telephone cables

  19. < Ex 6 WWW > Services on the Internet • World Wide Web • Newsgroups • Chat rooms • Search Engines • E-Commerce

  20. <- Broadband Browser example -> Browsers • Software that fetches and displays web pages • Most people use Internet Explorer • Hyperlinks let you click onto a new page • The browser will remember web pages for you using favourites

  21. History Favourites Forward and back buttons Hyperlink <- Browsers Online/Offline ->

  22. < Internet services Hyperlinks > The World Wide Web • Web pages stored in servers round the world • Web pages are multimedia documents • Linked with hyperlinks

  23. < Ex7 Newsgroup pic > Other services on the net • Newsgroups let you discuss particular subjects • Chat rooms let you talk live to other people • Netiquette is very important when using these services <superdave> I like rock’n’roll <megabrad> Dude what’s your favourite band????????1 <superdave> like, Nirvana dude <glasgowbob> haw naw m8 get a clue <megabrad> who is this glasgowbob? <glasgowbob> whit man watch oot <superdave> like whatever man <Teacher> hello chaps, what’s going on? <glasgowbob> aw naw teacher man, pure bolt ** glasgowbob has signed out

  24. < Other services Search Engines > Newsgroups

  25. < Newsgroups Search example > Search Engines • Simple searches – just type in a brief description Any search engine that you enter your brief description into a single search box uses simple search. • You can do this on: • Google • Yahoo • Google images

  26. Cloud Computing • Instead of buying and setting up a network, they have simple computing devices: • Which they use to access the internet • And use the software, backing storage and servers provided by the Cloud Computing company. • Basically, they rent the use of powerful network resources

  27. Cloud Computing: advantages • Cloud users: • can have access to powerful networks without having to spend lots of money setting up their own network = lower cost

  28. Cloud Computing: advantages • Cloud users: • can update and change their software as their needs change = flexibility • have access to technical support = lower maintenance / staff costs • are billed only for the services they use and the length of time they use them == lower cost • can easily scale up or down their network resources as their needs dictate =flexibility

  29. Cloud Computing: advantages • Backup and recovery of data is guaranteed by the Cloud Provider

  30. Cloud Computing: disadvantages • Security: having all an organisation’s data stored in ‘ the cloud’ can be a security risk e.g. from hackers, from malware • Many organisations keep ‘critical data’ backed up locally, just in case. • It depends on a reliable speedy internet connection • Can be locked into a contract

  31. Locally owned and managed network • Gives local control over • Security • Backup regime • But • Can cost a lot more to set up • Is not as flexible: not so easy to scale up or down the hardware and software

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