Book extract: design and validation of computer protocols
"The problem of designing efficient and unambiguous communication protocols existed long before the first computers were built. There is a long history of attempts to construct systems for transferring information quickly over long distances. From a protocol designer’s point of view, the mishaps that were caused by misinterpreted communications are fascinating...." 
(From Gerard J. Holzmann's excellent book on Protocol Validation)

"Formal Methods for Specification and Analysis of Communication Protocols" 
A comprehensive introduction to modeling and analysis of distributed systems and concurrent processes in telecommunications and protocol engineering. Covers estelle, SDL, SPIN, LOTOS, and Petri Nets, among others. Originally published in the December 2002 issue of "IEEE Communications Surveys & Tutorials", the complete paper is available for online viewing, with figures.
(View complete paper online )