|  | 12.2 | TCP and UDP
| 12.2.2 | UDP Segment Format

User Datagram Protocol (UDP) is the connectionless transport protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams, without acknowledgments or guaranteed delivery. Error processing and retransmission must be handled by other protocols.

UDP uses no windowing or acknowledgments, therefore application layer protocols provide reliability. UDP is designed for applications that do not need to put sequences of segments together.

Protocols that use UDP include:

- TFTP (Trivial File Transfer Protocol)
- SNMP (Simple Network Management Protocol)
- DHCP (Dynamic Host Control Protocol)
- DNS (Domain Name System)