TCP/IP Guide

The Robustness Principle

The TCP standard says that TCP follows the robustness principle, which is described in this way: "Be conservative in what you do; be liberal in what you accept from others." This rule means that every TCP implementation tries to avoid doing anything that would cause a problem for another device's TCP layer. At the same time, every TCP implementation is also trying to anticipate problems that another TCP may cause and attempting to deal with those problems gracefully.

This principle represents a "belt and suspenders" approach that helps provide extra protection against unusual conditions in TCP operation. In fact, this general principle is applied to many other protocols in the TCP/IP protocol suite, which is part of the ...