07/17/18

• Run length- changes to to # of things + thing
• Delete whitespace
• Just tell ending if beginning is same

2ND LAYER

• Network Interface Layer
• 8 bits
  • 8 wires or 1 wire
• Multiplexing
• Packet = chuck = frame = block
• Big-endian vs little-endian
  • Little-endian = least significant bit first
  • Big-endian = little endian
• 1 wire with a lot of clients
  • LANs = Local-Area Networks
  • Multiple access / shared medium
  • Gets on LAN through NIC - Network Interface Controller, aka LAN adapter
  • NIC’s exist on both the physical layer and the data link layer of the 5 layer model
  • NIC’s can be cards, part of the motherboard, PCMCIA expansion slots, or a USB device
• MAC Address
  • 48 bits
  • Hex
  • OUI - Organizational Unique Identifier
  • Unique- Vendor assigned
  • CSMA/CD - Ethernet
• Ethernet Protocol
  • Get a data packet
• Actual Protocol
• CSMA-CD
  • CS = carrier sense = listen before transmitting
  • MA = multiple access = everyone can hear everyone else
  • CD = collision detection = detect collision deal with them