Each layer of the OSI model has its own critical protocols. At the transport layer, TCP and UDP are fundamental. This course focuses on the understanding TCP and UDP operation

TCP is used in nearly every transaction users have on a network. Surfing the web, checking your email, watching a streaming video, all use TCP as the transport layer protocol. TCP has a very precise operation, and understanding how it works leads to becoming a great network troubleshooter. In this course, TCP and UDP Operation, you will learn about the TCP three-way handshake, port number addressing, and sequence and acknowledgment numbers used for reliable communication. Next, you explore at TCP's less reliable partner, UDP. Finally, you'll understand where UDP is used and why you use it. By the end of this course, you'll know how the TCP three-way handshake works, as well as how TCP uses sequence numbers to ensure successful data delivery.

https://www.pluralsight.com/courses/tcp-udp-operation