User Datagram Protocol

The User Datagram Protocol (UDP) is the other layer 4 protocol commonly used on modern networks. While TCP is designed for reliable data delivery with built-in error checking, UDP aims to provide speedy transmission. For this reason, UDP is a best-effort service, commonly referred to as a connectionless protocol. A connectionless protocol does not formally establish and terminate a connection between hosts, unlike TCP with its handshake and teardown processes.

With a connectionless protocol, which doesn’t provide reliable services, it would seem that UDP traffic would be flaky at best. That would be true, except that the protocols that rely on UDP typically have their own built-in reliability services, or use certain features ...

Get Practical Packet Analysis, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.