UDP
User Datagram Protocol
Feature
- Connectionless, unreliable
- Unicast and multicast
- Datagram oriented
UDP Format
![](/note/computer-network/transport-layer/udp/UDP%20Format_hu89ef0a656cae8465cce5751e160b22d8_91531_a0209e157267e9a5b6824c52eb84ec10.png)
- Port numbers
- Identify sending and receiving applications (processes). The maximum value for a port number is 216-1= 65535
- 1-1023: Well-known, used by servers, fixed
- 1024-49151: Registered, used by ordinary user processes
- $>$49151: Dynamic/private, used by clients, randomly picked