Networks
Mr Arthur
Aims of Lesson 1
1. Introduce networks
2. LANs
3. WANS
4. Transmission Media
5. Client Server and Peer-to-peer networks
Stand Alone/Networked
 A Stand Alone computer system is a computer that
is not connected to any other
 A network is a li...
Local Area Networks
 A LAN is a network of computers connected over a
small geographical area, usually inside the 1 build...
Wide Area Networks
 A WAN is a network of computers over a large
geographical area, such as across a country or the world...
Client Server Network
 A client-server network is where all resources are stored
centrally on the server and are assessed...
Peer to Peer Network
 A peer-to-peer network is where each station has its
own local storage device.
 Advantages
 Easie...
Aims of Lesson 2
Last Lesson
 Introduce networks
 LANs
 WANS
 Transmission Media
 Client Server and
Peer-to-peer netw...
Star Topology
 All peripheral nodes are
connected to a central node
 If a peripheral node fails it has no
effect on the ...
Ring Topology
 Signals are sent around the
network from node to node
 If a node is faulty, then
there must be a method o...
Bus Topology
 The bus topology has each node
connected to a main communication
channel (The Bus)
 If one node is faulty ...
Mesh Topology
 A mesh topology has
multiple direct connections
between each node
 The internet is an example
of a Mesh n...
Network Quiz
1. Give 3 functions of a LAN
2. Give 3 transmission media you would
associate with a LAN
3. Describe a client...
Aims of Lesson 3
Last Lesson
 Introduce networks
 LANs
 WANS
 Transmission Media
 Client Server and
Peer-to-peer netw...
Network Interface Cards
 Network Interface Cards = a small
printed circuit board inside the
computer system allowing it t...
Hotspots
 An area where network
signals may be received
 Usually located in built up
areas
 May be deliberate
hotspots ...
Router
 A router is a device
which links 2 or more
networks
 The router takes
packets of data and
decides which route
th...
HUBs
 A hub is a device with
multiple ports which
allows more than 1
device to share the
same wire
 The hub will also bo...
Switch
 A switch operates like a
smart hub
 The switch separates
the network into
segments
 More than one machine
can s...
Aims of Lesson 4
Last Lesson
 Introduce networks
 LANs
 WANS
 Transmission Media
 Client Server and Peer-to-
peer net...
Mainframes and
Supercomputers
 Mainframes
 A large powerful computer
which can process a very
large amount of data at a
...
Current Network Trends
 Higher Bandwidth
 Increasing amount of data carried
along communications channel
 Virgin Media ...
Technical Reasons for Increasing
Number of Networks
 Advances in computer hardware
 Faster, Multiple processors
 Cheape...
Final Network Lesson
Last Lesson
 Introduce networks
 LANs
 WANS
 Transmission Media
 Client Server and Peer-to-peer
...
File/Print/Web Servers
 File Server
 A file server provides central disk
storage for user’s programs and
data on the net...
Misuse of Networks
 Copyright Designs and Patents Act
 This makes it illegal to copy music,
programs, movies etc without...
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Network Slides

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

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