[[Networking]] [[Layer 4- Transport]]

Overview

• Layer 4 protocol used to transport smaller amounts of data
• Connection-less, message oriented. Best effort ## Uses of UDP
• SNMP/DNS: Generally small request and response. Does not require much overhead
• Realtime audio and video, streaming

• Protocol List

  • NTP Network Time Protocol - 123
  • DNS Domain Name Server - 53
  • DHCP Dynamic Host Control Protocol - 68
  • NNTP Network News Transport Protocol - 119
  • TFTP Trivial File Tranfser Protocol - 69
  • SNMP - 161
  • a few more… insignificant

UDP Header

• Source Port Number -> Destination Port Number -> Total Length -> Checksum
• Total Length = UDP header + L4 Payload; L3 Header + L3 Payload
• Source Port: Optional, if not used, value=0
• Destination Port: Destination port
• Length: FIXED at 8 BYTES
• Checksum: Ensures datagram has not been corrupted