Transport Layer

UDP

Connectionless transport protocol, no handshake, each segment is handled independently from others

UDP segment is very simple: an 8 byte header and a payload. It has a source port, destination port, length and checksum

The checksum in UDP is only for detection, not correction

As messages are transported through layers, they acquire new headers that wrap the existing packet

Checksum in UDP is actually optional but is required in TCP and IPv4