Source for Computer Networks: A Systems Approach is available on GitHub under terms of the Creative Commons (CC BY 4.0) license. The community is invited to contribute corrections, improvements, updates, and new material under the same terms. While this license does not automatically grant the right to make derivative works, we are keen to discuss derivative works (such as translations) with interested parties. Please reach out to [email protected].

Like many open source software projects, this one has been seeded with once restricted content: the 5th edition of Peterson and Davie, copyrighted by Elsevier. Our hope is that open sourcing this material will both make it widely available and serve as an attractor for new content: updating what’s already there, expanding it to cover new topics, and augmenting the text with additional teaching collateral.

If you make use of this work, the attribution should include the following information:

This book is part of the Systems Approach Series, with an online version published at https://book.systemsapproach.org.

To track progress and receive notices about new versions, you can follow the project on Mastodon. To read a running commentary on how the Internet is evolving, and for updates on our writing projects, you can sign up for the Systems Approach newsletter.

We release ever-changing open source content rather than publish fixed books, although you can roughly equate v6.0 with a 6th Edition. Read the :ref:`preface` to find out what’s new in this version. Note that Morgan Kaufmann (Elsevier) published the 6th edition of the textbook based on a fork of v6.0, but going forward, open source releases found here will not necessarily stay in sync with any future published editions.

In general, master contains a coherent and internally consistent version of the material. (If it were code, the book would build and run.) New content under development is checked into branches until it can be merged into master without breaking self-consistency. The web version of the book available at https://book.systemsapproach.org is then continuously generated from master, corresponding to a typical maintenance release (although we do not bother to tag it as such).

Minor releases (e.g., v6.1) are tagged whenever there is sufficient new content to justify the effort. This happens quarterly, give-or-take, and is primarily to create a snapshot so that everyone in a course can know they are using the same version.

To build a web-viewable version, you first need to download the source:

$ mkdir ~/systemsapproach
$ cd ~/systemsapproach
$ git clone https://github.com/systemsapproach/book.git
$ cd book

The build process is stored in the Makefile and requires Python be installed. The Makefile will create a virtualenv (venv-docs) which installs the documentation generation toolset. You may also need to install the enchant C library using your system’s package manager for the spelling checker to function properly.

To generate HTML in _build/html, run make html.

To check the formatting of the book, run make lint.

To check spelling, run make spelling. If there are additional words, names, or acronyms that are correctly spelled but not in the dictionary, please add them to the dict.txt file.

To see the other available output formats, run make.

We hope that if you use this material, you are also willing to contribute back to it. If you are new to open source, you might check out this How to Contribute to Open Source guide. Among other things, you’ll learn about posting Issues that you’d like to see addressed, and issuing Pull Requests to merge your improvements back into GitHub.

If you do want to contribute either patches or new material, you will need to sign a Contributor Licensing Agreement (CLA). You’ll be prompted to sign the CLA the first time you make a pull request.

The CLA is pretty straightforward: it establishes that (a) you have the right to contribute what you’re contributing, and (b) what you contribute is available to everyone else under the same CC BY terms as the existing content. The CLA is a little unusual in that it explicitly calls out Elsevier’s rights (which are the same as everyone’s), but this does signal their intent to continue publishing textbooks based on the material.

You should also familiarize yourself with the guidelines for contributing.

If you’d like to contribute and are looking for something that needs attention, see the current Project Board. We’d also like to expand the set of topics/chapters beyond the initial set inherited from the 5th edition, so if you have ideas, we’d love to hear from you. Send email to [email protected], or better yet, join the forum.

Finally, in as much as this is an on-going effort, we will try to record and track our progress. For now, think of this as a poor-man’s release notes. Additional information about work-in-progress can be found in the wiki.

We hope you’ve gotten value out of Computer Networks: A Systems Approach over the years, and we’re eager to have you join us in this new venture.