[In English only, but under a free licence.]
Je ne l’ai pas encore lu mais l’auteur est quelqu’un de très bien et très connu.
►http://inl.info.ucl.ac.be/CNP3
Computer Networking : Principles, Protocols and Practice (aka CNP3) is an ongoing effort to develop an open-source networking textbook that could be used for an in-depth undergraduate or graduate networking courses.
The textbook uses the top-down approach initially proposed by Jim Kurose and Keith Ross for their Computer Networks textbook published by Addison Wesley. CNP3 is distributed under a creative commons license.