Mythology and folklore of network protocols

It's natural to assume that network protocol design is by now a well-known science, where the designers of today's standards take care to understand the tricks and pitfalls learned from previous protocols. This talk dispells this and other myths. It is intended to be provocative, making people question the things people assume are true; instructive, giving hints as to how to avoid some of the problems in future protocols; and inspirational, convincing students that there are ample opportunities to make contributions. This talk discusses wrong turns that have been made, such as what necessitated the invention of bridges, and what caused IP multicast to be unimplementable. It also talks about how a protocol, even one “proven correct”, can go horribly wrong, such as the unstable ARPANET protocol for distributing routing information. It talks about “obvious” tricks such as version numbers, that even today protocol designers insist on misusing. And it covers some of the areas in which research is most needed.