WANs and LANs

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

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WANs and LANs

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	Created by Josh Watkins about 7 years ago