Network Slides


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Network Slides

  1. 1. Networks Mr Arthur
  2. 2. Aims of Lesson 1 <ul><li>Introduce networks </li></ul><ul><li>LANs </li></ul><ul><li>WANS </li></ul><ul><li>Transmission Media </li></ul><ul><li>Client Server and Peer-to-peer networks </li></ul>
  3. 3. Stand Alone/Networked <ul><li>A Stand Alone computer system is a computer that is not connected to any other </li></ul><ul><li>A network is a linked set of computer systems that are capable of sharing programs, data and sending messages </li></ul>
  4. 4. Local Area Networks <ul><li>A LAN is a network of computers connected over a small geographical area, usually inside the 1 building </li></ul><ul><li>Examples </li></ul><ul><ul><li>School LAN </li></ul></ul><ul><ul><li>Network in a library </li></ul></ul><ul><li>Uses </li></ul><ul><ul><li>Sharing resources </li></ul></ul><ul><ul><li>Sharing peripherals </li></ul></ul><ul><ul><li>Email </li></ul></ul><ul><li>Transmission Media </li></ul><ul><ul><li>Copper Wire, Fibre Optic and Wireless </li></ul></ul>
  5. 5. Wide Area Networks <ul><li>A WAN is a network of computers over a large geographical area, such as across a country or the world. </li></ul><ul><li>Examples </li></ul><ul><ul><li>The Internet </li></ul></ul><ul><ul><li>Companies like the BBC communicating across the world </li></ul></ul><ul><li>Uses </li></ul><ul><ul><li>video-conferencing, use of e-mail, live chat </li></ul></ul><ul><ul><li>Sharing Information - access to databases, </li></ul></ul><ul><ul><li>E-commerce and entertainment </li></ul></ul><ul><li>Transmission Media </li></ul><ul><ul><li>Fibre Optic, Microwave transmission and Satellite </li></ul></ul>
  6. 6. Client Server Network <ul><li>A client-server network is where all resources are stored centrally on the server and are assessed by the client stations </li></ul><ul><li>Advantages </li></ul><ul><ul><li>Increased security as each user needs to log in </li></ul></ul><ul><ul><li>Different levels of access are available </li></ul></ul><ul><ul><li>Users can work on the same document at the same time </li></ul></ul><ul><ul><li>Flexible uses of station, you can log on to a number of clients and access your files </li></ul></ul><ul><ul><li>Backup copies are completed centrally </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>If the file server is down there is no access to data </li></ul></ul><ul><ul><li>More expensive as you need to buy a server and server software </li></ul></ul>
  7. 7. Peer to Peer Network <ul><li>A peer-to-peer network is where each station has its own local storage device. </li></ul><ul><li>Advantages </li></ul><ul><ul><li>Easier to setup operating systems on stations in a peer-to-peer </li></ul></ul><ul><ul><li>Cheaper as no server is required </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>No central file storage – users must log in to the same station to access files </li></ul></ul><ul><ul><li>Users must backup their own data </li></ul></ul><ul><ul><li>Peer-to-peer is less secure as users may not be required to log in </li></ul></ul>
  8. 8. Aims of Lesson 2 <ul><li>Last Lesson </li></ul><ul><li>Introduce networks </li></ul><ul><li>LANs </li></ul><ul><li>WANS </li></ul><ul><li>Transmission Media </li></ul><ul><li>Client Server and Peer-to-peer networks </li></ul><ul><li>Today’s Lesson </li></ul><ul><li>Network Topologies </li></ul><ul><li>Network Interface Cards </li></ul><ul><li>Hotspots </li></ul>
  9. 9. Star Topology <ul><li>All peripheral nodes are connected to a central node </li></ul><ul><li>If a peripheral node fails it has no effect on the network </li></ul><ul><li>If the central node fails the whole network is “down” </li></ul><ul><ul><li>Advantage = Easy to add new stations </li></ul></ul><ul><ul><li>Disadvantage = Central node may get congested with network traffic </li></ul></ul>
  10. 10. Ring Topology <ul><li>Signals are sent around the network from node to node </li></ul><ul><li>If a node is faulty, then there must be a method of bypassing the failed node </li></ul><ul><li>If a communications channel fails, the network fails </li></ul>
  11. 11. Bus Topology <ul><li>The bus topology has each node connected to a main communication channel (The Bus) </li></ul><ul><li>If one node is faulty this has no effect on the rest of the network </li></ul><ul><li>If the bus is faulty, the whole network is “down” </li></ul><ul><ul><li>Advantage = Easy to add new stations </li></ul></ul><ul><ul><li>Disadvantage = Each node may have to compete with each other in order to transmit and receive data </li></ul></ul>
  12. 12. Mesh Topology <ul><li>A mesh topology has multiple direct connections between each node </li></ul><ul><li>The internet is an example of a Mesh network </li></ul><ul><ul><li>Advantage = A node failure has no effect on the rest of the network </li></ul></ul><ul><ul><li>Disadvantage = Expensive to set up with a lot of cabling </li></ul></ul>
  13. 13. Network Quiz <ul><li>Give 3 functions of a LAN </li></ul><ul><li>Give 3 transmission media you would associate with a LAN </li></ul><ul><li>Describe a client server network (2) </li></ul><ul><li>Give 2 advantages of a client server over a peer to peer network </li></ul><ul><li>Describe a peer to peer network </li></ul>
  14. 14. Aims of Lesson 3 <ul><li>Last Lesson </li></ul><ul><li>Introduce networks </li></ul><ul><li>LANs </li></ul><ul><li>WANS </li></ul><ul><li>Transmission Media </li></ul><ul><li>Client Server and Peer-to-peer networks </li></ul><ul><li>Network Topologies </li></ul><ul><li>Today’s Lesson </li></ul><ul><li>Network Interface Cards </li></ul><ul><li>Hotspots </li></ul><ul><li>Router </li></ul><ul><li>Hubs </li></ul>
  15. 15. Network Interface Cards <ul><li>Network Interface Cards = a small printed circuit board inside the computer system allowing it to communicate with the network. </li></ul><ul><li>The NIC provides the computer with a unique Media Access Control (MAC) address made up of 6 bytes </li></ul>
  16. 16. Hotspots <ul><li>An area where network signals may be received </li></ul><ul><li>Usually located in built up areas </li></ul><ul><li>May be deliberate hotspots in a University or may be accidentally created </li></ul><ul><ul><li>Warchalking </li></ul></ul><ul><ul><li>Wardriving </li></ul></ul>
  17. 17. Router <ul><li>A router is a device which links 2 or more networks </li></ul><ul><li>The router takes packets of data and decides which route through the network the packet should take </li></ul>
  18. 18. HUBs <ul><li>A hub is a device with multiple ports which allows more than 1 device to share the same wire </li></ul><ul><li>The hub will also boost or amplify signals </li></ul><ul><li>Multi-port repeater </li></ul>
  19. 19. Switch <ul><li>A switch operates like a smart hub </li></ul><ul><li>The switch separates the network into segments </li></ul><ul><li>More than one machine can speak at once and only the intended recipients receives the signal </li></ul>
  20. 20. Aims of Lesson 4 <ul><li>Last Lesson </li></ul><ul><li>Introduce networks </li></ul><ul><li>LANs </li></ul><ul><li>WANS </li></ul><ul><li>Transmission Media </li></ul><ul><li>Client Server and Peer-to-peer networks </li></ul><ul><li>Network Topologies </li></ul><ul><li>Network Interface Cards </li></ul><ul><li>Hotspots </li></ul><ul><li>Router </li></ul><ul><li>Hubs </li></ul><ul><li>Today’s Lesson </li></ul><ul><li>Mainframes/Super computers </li></ul><ul><li>Current network trends </li></ul><ul><li>Technical reasons for increasing number of networks </li></ul>
  21. 21. Mainframes and Supercomputers <ul><li>Mainframes </li></ul><ul><li>A large powerful computer which can process a very large amount of data at a high speed </li></ul><ul><li>May be connected to hundreds of dumb terminals </li></ul><ul><li>Multi -programming </li></ul><ul><li>Multi -tasking </li></ul><ul><li>Multi -processors </li></ul><ul><li>Supercomputers </li></ul><ul><li>More powerful than a Mainframe </li></ul><ul><li>Supercomputers are used for intensive mathematical calculations like weather forecasting, aerospace engineering </li></ul>
  22. 22. Current Network Trends <ul><li>Higher Bandwidth </li></ul><ul><ul><li>Increasing amount of data carried along communications channel </li></ul></ul><ul><ul><li>Virgin Media advertising 20Mbps!!! </li></ul></ul><ul><ul><li>There will be a limit however, depending on the distance from subscriber and the telephone exchange </li></ul></ul><ul><li>Wireless Functions </li></ul><ul><ul><li>WiFi, Bluetooth, Zigbee </li></ul></ul>
  23. 23. Technical Reasons for Increasing Number of Networks <ul><li>Advances in computer hardware </li></ul><ul><ul><li>Faster, Multiple processors </li></ul></ul><ul><ul><li>Cheaper, higher capacity RAM chips </li></ul></ul><ul><ul><li>Increasing Backing storage capacities </li></ul></ul><ul><ul><li>Increasing data transfer rates </li></ul></ul><ul><li>Improved Network software </li></ul><ul><ul><li>Browsers = improved functionality using plug-ins, allowing streamed video, animated graphics to be displayed </li></ul></ul><ul><ul><li>Operating Systems designed with networking functions built in </li></ul></ul>
  24. 24. Final Network Lesson <ul><li>Last Lesson </li></ul><ul><li>Introduce networks </li></ul><ul><li>LANs </li></ul><ul><li>WANS </li></ul><ul><li>Transmission Media </li></ul><ul><li>Client Server and Peer-to-peer networks </li></ul><ul><li>Network Topologies </li></ul><ul><li>Network Interface Cards </li></ul><ul><li>Hotspots </li></ul><ul><li>Router </li></ul><ul><li>Hubs </li></ul><ul><li>Mainframes/Super computers </li></ul><ul><li>Current network trends </li></ul><ul><li>Technical reasons for increasing number of networks </li></ul><ul><li>Today’s Lesson </li></ul><ul><li>File, Print and Web servers </li></ul><ul><li>Legislation </li></ul><ul><ul><li>Computer Misuse Act </li></ul></ul><ul><ul><li>Copyright Designs and patents act </li></ul></ul><ul><ul><li>Data Protection Act </li></ul></ul>
  25. 25. File/Print/Web Servers <ul><li>File Server </li></ul><ul><ul><li>A file server provides central disk storage for user’s programs and data on the network </li></ul></ul><ul><ul><li>The file server will run 24 hours a day and must have a fast processor, lots of RAM and much larger hard disk capacity </li></ul></ul><ul><ul><li>Controls security on the network </li></ul></ul><ul><ul><li>Backed up using a Digital Audio Tape (DAT) </li></ul></ul><ul><li>Print Server </li></ul><ul><ul><li>A print server will allow multiple clients share the same printer </li></ul></ul><ul><ul><li>The print server will use a spooler program and the printer will probably have a buffer as well </li></ul></ul><ul><li>Web server </li></ul><ul><ul><li>A web server is a computer that provides WWW services to a network </li></ul></ul><ul><ul><li>You have the benefit of “always on” fast access to pages </li></ul></ul><ul><ul><li>Every computer that host a website must have a web server program </li></ul></ul>
  26. 26. Misuse of Networks <ul><li>Copyright Designs and Patents Act </li></ul><ul><ul><li>This makes it illegal to copy music, programs, movies etc without the permission of the owner </li></ul></ul><ul><li>Computer Misuse </li></ul><ul><ul><li>Makes it illegal to hack or spread viruses </li></ul></ul><ul><li>Data Protection Act </li></ul><ul><ul><li>Controls the storage of personal information </li></ul></ul>