Lecture 9: The Transport Layer; UDP

A logical connection between network hosts

This is the first lecture in a series exploring the Transport layer. This layer is responsible for logical communication between applications running on (usually) different hosts. As such, it is designed with careful consideration for the requirements of a class of applications. Because of the diversity in applications, there is a need for several different types of transport protocols. This lecture will take a look at the simplest such transport protocol -- the User Datagram protocol or UDP. UDP is useful for situations where the application cannot allow for the delays inherent in other reliable transport protocols. UDP itself has no packet-to-packet reliability (it does have checksums to allow for error determination), so applications making use of UDP either do not have need of reliable communication or they prefer to provide more custom reliability services.

Lesson Objectives

By the end of this lesson, the student will be able to: