The Internet Protocol Journal, Volume 11, No. 1

Book Review

Patterns in Network Architecture

Patterns in Network Architecture: A Return to Fundamentals, by John Day, ISBN-10: 0132252422, ISBN-13: 9780132252423, Prentice Hall, 2007. http://www.informit.com/store/product.aspx?isbn=0132252422

It isn't every day (pun intended) that one of the true Old Guard writes and publishes a book, and it behooves us to take notice. In this case, the author's expertise and his subject matter are of particular timeliness, because of the worldwide resurgence of activities with regard to next-generation network architectures, that is, a replacement, or upgrade to the Internet (dare one say "Internet 2.0"?).

John Day is a well-known scholar of historical cartography, and this book, in a way, is a roadmap of network architecture. The roadmap starts back in 1970, tracing from the roots of connectionless packet-switched dynamically routed systems such as Cyclades, and the ARPANET, through to recent discussions on multihoming, multicast, and mobility, with a view along the way of naming, addressing, protocol stack design, protocol design, and concepts of layering.

That description makes the book sound fairly standard in terms of structure and content, but it isn't. The book includes many discursive elements whose intent is to provide a collection of patterns. Design patterns originated in the building trade as a way for crafts people to pass on successful methods of construction (in the sense of affordable and noncollapsing) to less-inventive people (or people who want to spend their inventive efforts in different areas). Software engineers picked up on this idea, applying the techniques in both the microscopic world: patterns allow you to decide what algorithm is applicable in solving a problem in the small; and the macroscopic world: architectural patterns allow you to decide on an approach to breaking down a large system into the right kind of components.

Essentially, this book does the same thing, at the protocol stack level, and at the system level, with a collection of historical and contemporary examples to support the arguments.

The book makes interesting reading, especially as it represents a fair balance in reporting the early ideas that came not just from the United States, and restates the importance of the Opens Systems Interconnection (OSI) model (not the ISO protocols) in understanding layering and beads-on-a-string, as well as reasserting the use of the model in clarifying the perennially confusing concepts of names, addresses, and routes.

The book begins with a discussion of seven principles that emerged through the early history of networking (I won't spoil the book for readers by listing them here), and ends in the tenth and final chapter, entitled "Backing Out of a Blind Alley," with an appeal to fundamentals. Essentially, the author points out that researchers (especially academics) are strongly motivated to keep moving on with claims of ever-newer tricks, but rarely to consolidate these tricks into a set of principles that stand for a long time (because then they would have to completely change the topic of their research). Thus uncovering a foundational theory of networking would put a whole generation of networkers out of work (or funding at least).

The book is peppered (saltily) with fine quotes and fascinating asides from philosophy (for this reader, especially, the Chinese diversions were most novel and illuminating). Illustrative of the range is that one finds Wittgenstein and Dave Clark, Confucius, and Dr. Seuss—Frege's useful reminder that "The sign '=' should be read as 'is easily confused with'" would make an excellent IETF T-shirt.

I found the book extremely readable and enjoyable, and although I might argue with some of the opinions in the book, I think that this is just more evidence that I should recommend the book to anyone interested in knowing why we are where we are in networking, and being better informed about where we should go next.

—Jon Crowcroft, University of Cambridge
Jon.Crowcroft@cl.cam.ac.uk

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