1.4 Wired and Wireless Networks

CLIENT SERVER
1. receives and processes requests from clients
  1. what user does on computer is sent to central computer
    1. workers can update central databases
      1. server stores users account details
2. ADV.
  1. easier security management
    1. easier backups of shared data
      1. easier to install software updates to all devices
  2. DISADV.
    1. expensive to set up+maintain
      1. requires IT specialists to maintain
        server=sing. point of failure
PEER-PEER
1. all computers have equal status
2. ADV
  1. cheaper to set up
    1. relatively easy to maintain
      1. allow individual devices to share files between each other
        no dependance on server
        no need for network manager
  2. DISADV.
    1. less secure network
      1. users manage own backups
        difficult to maintain well ordered store of files
WAN
1. telecommunication company provides infrastructure
  1. larger geographical area
LAN
1. own infrastructure
  1. telecommunication owned by organization
    1. Local Area Network
      1. small geo area
        HARDWARE
        NIC
        connects device to wireless/wired network
        uses protocols
        WAP
        allows wireless-enabled devices to access net. without cables
        bandwidth=lower
        security=weak
        SWITCH
        sends data between com on LAN
        only send traffic to correct device
        unrecognisable= broadcast packet to all connections
        ROUTER
        sends data between networks on WAN
        cannot access WAN without it
        uses IP address
DNS SERVER
1. Domain Name System
  1. has list of all domain names and IP addresses
    1. hosting
CLOUD COMPUTING
1. load files from any location and any time
  1. data automatically backed up
    1. large capacity
      1. share files easily
VIRTUAL NETWORK
1. part of a LAN/WAN
  1. configured so that certain devices can see each other
2. SCALABILITY
  1. users can be connected to diff. switches but appear to be in same network
    1. bandwidth used more efficiently
  2. SECURITY
    1. users cant access other devi.
    2. COST
      1. don't need to change infrastructure as busi. changes
VPN
1. Virtual Private Network
  1. send data securely over a WAN
PACKETS
1. Packet number
  1. Sender and receivers IP address
    1. internet protocol
      1. set of rules that govern how devices communicate
CABLES
1. FIBRE OPTIC
  1. doesn't suffer from electrical interference
    1. transmit data through light
      1. covers longer distances
        higher bandwidth
2. COPPER
  1. electric conductor
    1. cheap +flexible
    2. e.g. STP, UTP
  2. disadvantages
    1. shorter lifespan
      1. corrosion
        affects quality of bandwidth
WHAT AFFECTS PERFORMANCE OF NETWORK?
1. cable(transmission media)
  1. bandwidth - amount of data that can be transmitted in a certain amount of time
    1. no.of users
      1. distance - weaker signal if far
        latency - caused by bottlenecks in infrastructure

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1.4 Wired and Wireless Networks

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	Criado por kimi rod mais de 6 anos atrás