• Stands for Carrier Sense Multiple Access
  • Basically multiple Host share the same Carrier to communicate


Computers need to know if it should process the incoming data

  • When one computer sends a piece of data to another computer, the other computers sharing the same Carrier will also receive the data
  • This can be solved using MAC Address. The computer only processes the data when the recipient address matches it’s MAC address in the data

Collision among computers



  • Refers to any shared transmission medium
  • Copper wire in the case of Ethernet
  • Air carrying radio waves for Wi-Fi

Multiple Access

  • Refers to many computers can send Data over the same Carrier simultaneously


  • Happens more than one computer on the Carrier sand Data at the same time
  • Data in the Carrier will get messed up, requires a re-send
  • Can be detected by listening on the signals on the Carrier