Introduction to Networks

Networks

• • How can 2 computers talk to each other? 
    • through network
    • most people buy a wireless router to connect  things together
• LAN = Local Area Network
• • • combination of router, computer systems, wireless router
• NIC = Network Interface Card
• • • ear and mouth of a computer: receive and transmit information
• WAN = Wide Area Network
• • • connect networks across multiple cities, countries, etc;
    • to connect network in buildings and different floors (creating a small WAN): 
      • connect all systems on a floor with a router
      • connect all floors in a building with another router
• Mac Address
• • • how computers identify or communicate with each other
    • unique to each computer’s network interface card
    • format: 00:00:AB:13:5A:2C, or 0000.AB13.5A2C
      • represented in hexadecimals
      • 6 bytes long, 48 bits
  • Computer’s Communicating
    • computers share a medium
• Collision Detection/Avoidance
• • originally: A talks to B, while B is talking to A, then there is interference and A’s message to B is lost
  • now: before C sends data to A, sees if there is a conversation going on with A, and only sends when A is free