TCP/IP Illustrated - Oleg V. Titov, CTD IFMO RU

This book describes the TCP/IP protocol suite, but from a different perspective than other texts on TCP/IP. Instead of just describing the protocols and what they do, we'll use a popular diagnostic tool to watch the protocols in action. Seeing how the protocols operate in varying circumstances provides a greater understanding of how they work and why certain design decisions were made: it also provides a look into the implementation of the protocols, without having to wade through thousands of source code.