This is an excellent reference book for Ethernet networking. Read the whole thing and you will know more than most network administrators about network hardware, network topologies, and pros and cons of various alternative ways of building a network top to bottom (at least up to the point where it joins your computer). Incidentally, the book's introduction and first chapter also do a really good job of explaining why Ethernet works so well (having defeated all other would-be networking standards such as token ring).

From time to time I check to see if it's been updated. I'm always slightly disappointed that it hasn't, but then I realize it doesn't need an update just yet because Ethernet technology is mature now and the changes are incremental. But rest assured that when O-Reilly updates it, I will buy it again because this is one of those books that I have to have handy.

The book goes into perfect detail as to why Ethernet based networks do this and that while delivering everything our computers request. The illustrations are perfectly clear. It is one I reccomend above all others.

First I read the standard, which destroyed my brain temporarily. Then I read this book. Then I went back to the 802.3, but with a much greater comfort. Here's the deal: the book is practical, for example, it tells you what's used and what's not. The standard legislates everything, but in reality a good part of it you don't need. Out of XXBaseT protocols you need only 10/100/1000Base-T/X. You wouldn't know this w/o the book. That's just one example. In general, this book simplifies matters, clarifies, puts everything in a realistic perspective: I've found it an easy, reasonably quick, and very helpful read.

Now, if I were to nitpick, I'd mention an intermittent conceptual muddle-headedness the author suffers from: for example, on page 23, he defines the notion of "half-duplex" as follows: "Half-duplex simply means that only one computer can send data over the Ethernet channel at any give time". This is incorrect. Half-duplex is a mode of communications where data can flow in only one direction at a time. How many computers take part is irrelevant to the definition. Now, the original Ethernet happens to be run over a shared medium, and it is _this_ fact that _necessitates_, as a ramification, the use of half-duplex over it, and, in turn, that only one station can talk at a time. A definition is different from a corollary, this is obviously unknown to the author. There are a couple of typos (nothing much, really, "bag full" instead of "bagful", this kind of stuff, nothing proofreading or an editorial intervention would not solve.)

Overall the book's very useful, recommended.

At the same time, do not believe it _alone_ is sufficient: at some point, you'll have to visit the IEEE site and download 802.3 itself (and the LLC perhaps; and MAC bridging too, most likely) -- all in all about 1500-2000 pages. That'll make your brain hurt, but the book will help quite a bit.

Btw, the standard isn't badly written: it's very clear, amazingly so at times; the difficulty is in its being detailed and precise; it's lawyerly reading, really. Not easy. Get the standard first, read it, don't try to memorize or even understand everything, just make one pass over it. Take a few days off to recover, then read this book. Then go back to the standard: it'll become much more meaningful now, smoother. That's what I did, and I think it's a good way to learn Ethernet.

A couple of points about other reviews here: the ones that say the book is not practical, are correct in a sense: it's not a net admin's installation manual (take this, plug it here, close the box, buy Cisco box ABC, type this into console, etc.) It's higher-level, it's an overview, it's fundamentals. I think it is so by design and don't consider it a flaw. If you need to configure a Cisco box, get a Cisco book; this book won't help you much with any vendor specifics.

Another reviewer whines about the lack of ARP coverage; this one is speaking out of ignorance: ARP is an IP, not Ethernet artefact (and so is reading analyzer traces). ARP is used to get IP addresses, who are, by definition above anything 802.3 covers. (Btw, ARP does get mentioned, though not in any degree of depth). One needs to understand the OSI layering to know what belongs where and not confuse things. Any book on the IP protocol stack will cover ARP; this one doesn't need to, it's outside of its scope.

Once again, a good book.

This book covers everything most people will ever want to know about Ethernet. Protocols, Ethernet Media, system Configuration, hubs, switches and troubleshooting. Signal encoding "The 5-4-3 Rule" even fiber optics. It's all here. In one book. Read the glossary first if your new to networking. This is a must have reference for anyone dealing with Ethernet issues.

This book covers a wide range of ethernet issues including fiber optics, 1000BASE-X, hubs, switches and trouble Shooting. This is an excellent reference. The glossary was better than average. Ethernet the Definitve Guide covers everything most people will ever want to know ethernet networking.