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WANs and LANs

Josh Watkins Computing GCSE Inglés 5,0Valoración media 5,0 de 5 (3 valoraciones)

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WANs and LANs

LANs
- Advantages
  - Enables Digital Communication
  - Enables Sharing of Information
  - Enables sharing of peripherals
  - Enables distributed processing
    - Multiple computers simultaneosly running the same program
  - Enables multiple computers to be updated from one central point
- Disadvantages
  - Requires some expertise to install and maintain
    - Costly
  - security issues
    - Viruses
    - Hackers
    - Spyware
- Hardware Needed
  - Multiple computers/nodes
    - All with a Network Interface Card
  - Data Transfer Media
    - Wires
    - Wireless Technology
  - Hub or Switch
  - Router
- Types of Network
  - Peer-to-Peer
    - All nodes have the same status
    - Data transfer may be slow
      - Data collisions
      - Shared process power
    - Only suitable for low-traffic networks
  - Client-Server
    - One computer is the server
      - This computer needs to be high spec
      - Large networks may have multiple servers
      - Clients must sign in so their identification is known
      - Jobs
        To manage traffic on a network
        To give security to users
        To offer services like software and data to the clients
  - Topologies
    - Bus
      - Cheap
      - If the main cable breaks the whole network may suffer
    - Ring
      - No data collisions
      - If the main cable breaks the whole network may suffer
    - Star
      - Very reliable
      - Very expensive
WANs
- Internet Protocols
  - Addressing Protocols
  - Data Transfer Protocols
  - A group of protocols that underlies the internet
  - There are many other specific protocols for particular tasks
- Every node on a network has an IP
  - 'Internet Protocol' - a unique sequence of four octets
  - This may not remain the same when it rejoins a network
- Each device has a MAC address hardwired into it
  - 'Media Access Control' - 12-digit hexadecimal number
  - Cannot be changed
- Packets
  - When data is sent across a network it is split into packets
  - Packet structure
  - Packet Address
    - The data is set from router to router until it reaches its destination
- Security
  - Access Levels
  - Passwords
  - Encryption
- Policies
  - Acceptable use policies outline how people should behave when using a network
  - Sanctions/punishments for those who don't use them properly
- Disaster Recovery
  - RAID
    - backup
  - Surge protector
    - reduces likelihood of overloading in the event of a power surge
  - Back up generator
  - Security
  - Failover
    - Making a system unbreakable
  - Regular Archiving
By Josh Watkins