1.4 Wired and Wireless Networks

1.4 Wired and Wireless Networks

1. CLIENT SERVER

   • receives and processes requests from clients
     • what user does on computer is sent to central computer
       • workers can update central databases
         • server stores users account details
   • ADV.
     • easier security management
       • easier backups of shared data
         • easier to install software updates to all devices
     • DISADV.
       • expensive to set up+maintain
         • requires IT specialists to maintain
           • server=sing. point of failure

2. PEER-PEER

   • all computers have equal status
   • ADV
     • cheaper to set up
       • relatively easy to maintain
         • allow individual devices to share files between each other
           • no dependance on server
             • no need for network manager
     • DISADV.
       • less secure network
         • users manage own backups
           • difficult to maintain well ordered store of files

3. WAN

   • telecommunication company provides infrastructure
     • larger geographical area
       • Internet is an example

4. LAN

   • own infrastructure
     • telecommunication owned by organization
       • Local Area Network
         • small geo area
           • HARDWARE
             • NIC
               • connects device to wireless/wired network
                 • uses protocols
               • Network interface card
             • WAP
               • allows wireless-enabled devices to access net. without cables
                 • bandwidth=lower
                   • security=weak
               • Wireless Access Point
             • SWITCH
               • sends data between com on LAN
                 • only send traffic to correct device
                   • unrecognisable= broadcast packet to all connections
               • Connects devices together on a network
             • ROUTER
               • sends data between networks on WAN
                 • cannot access WAN without it
                   • uses IP address

5. DNS SERVER

   • Domain Name System
     • has list of all domain names and IP addresses
       • hosting

6. CLOUD COMPUTING

   • load files from any location and any time
     • data automatically backed up
       • large capacity
         • share files easily

7. VIRTUAL NETWORK

   • part of a LAN/WAN
     • configured so that certain devices can see each other
   • SCALABILITY
     • users can be connected to diff. switches but appear to be in same network
       • bandwidth used more efficiently
     • SECURITY
       • users cant access other devi.
       • COST
         • don't need to change infrastructure as busi. changes
   • software based
   • needs username / password to access

8. VPN

   • Virtual Private Network
     • send data securely over a WAN

9. PACKETS

   • Packet number
     • Sender and receivers IP address
       • internet protocol
         • set of rules that govern how devices communicate

10. CABLES

    • FIBRE OPTIC
      • doesn't suffer from electrical interference
        • transmit data through light
          • covers longer distances
            • higher bandwidth
              • expensive
    • COPPER
      • electric conductor
        • cheap +flexible
        • e.g. STP, UTP
      • disadvantages
        • shorter lifespan
          • corrosion
            • affects quality of bandwidth

11. WHAT AFFECTS PERFORMANCE OF NETWORK?

    • cable(transmission media)
      • bandwidth - amount of data that can be transmitted in a certain amount of time
        • no.of users
          • distance - weaker signal if far
            • latency - caused by bottlenecks in infrastructure