Network Protocols

• A network protocol is a set of rules that define how data is transmitted between connected devices
• Protocols exist for any data exchange between two devices
• Common decisions made in a protocol include:

  • How communication should start and end (handshaking)
  • How data should be structured
  • Which network port communication should be over
  • How to check if the received data is correct
  • What to do if something goes wrong
• Transmission Control Protocol (TCP) splits data from applications into small pieces called 'packets'
• Each packet in TCP has a header (data about how the packet should reach its destination) and a payload (the actual data that needs to be sent)
• Ethernet is a protocol that defines how data should be physically transmitted between network hardware
• Ethernet is used in wired networks
• WiFi (802.11x) is a set of protocols defining how data should be transmitted using radio waves
• WiFi is used in wireless networks
• Internet Protocol (IP) defines how data packets should be sent between networks
• An IP header is added to each packet with the source and destination IP address
• Routers use IP information to deliver the packet to the correct network