Review of Fibre Channel

Fibre Channel
Alan F. Benner

Reviewed by Nick Christenson,

May 22, 1998

Fibre Channel is a promising new technology that can be used to transport either a channel technology, like the more familiar SCSI, or it can be used as a networking technology, like Ethernet. It's also designed to work at speeds of 1 Gbps (gigabit per second) now, and at higher speeds in the future. In order to accommodate such a wide range of potential uses and such extreme performance, the protocol itself is fairly complicated. This book is a description of this protocol, an exploration of what makes it so novel, and provides some ideas as to how it may be improved upon in the future.

When a book strives to be a description of a protocol or other new technology, it can be difficult to separate one's review of the book from a review of the technology being written about. I'm a big proponent of Fibre Channel technology for all kinds of uses, and while I will endeavor to primarily review the book here, I feel it's only fair to warn the reader of any biases that might creep in.

Fibre Channel starts with an introduction that includes some background information about the goals of the book and the Fibre Channel protocol. Benner gets into the thick of things pretty quickly, and if one doesn't already understand the basics of data encoding on physical media, one can get left behind pretty quickly. Some introductory information is presented here, but probably not enough to allow someone with some background in other LAN protocols to keep up very well. I'd strongly recommend the potential reader to read Held's Ethernet Networks or Jain's FDDI Handbook first if they have little experience working with the first two layers of the OSI reference model.

In the second chapter, Benner outlines the rest of the book. The Fibre Channel protocol is divided into layers more finely than the OSI reference model. These are designated FC-0 through FC-4 and cover up through the network layer in the OSI reference model. This chapter does a good job of providing an introduction to what's going on at each level. In fact, unless one is planning on writing a device driver, developing an interface card, or just really wants to roll up their sleeves, there may very well not be a need to read much past page 43.

Most of the rest of the book develops in detail the outline presented in chapter 2. The level of detail is exacting. I don't think I've seen a more thorough discussion of any protocol, although this is in large part due to the complexity of Fibre Channel.

The last chapter covers the future of Fibre Channel, namely, those extensions to the protocol that may be included in the FC-PH-2 standard. Some of these notions are really exciting, although to be fair, this is a tribute more to the possibilities of the protocol than the work of the author in this case.

There are a couple of key places where Benner does a very good job of explaining the details of what's going on under the hood. One of these is in the explanation of the low level 8B/10B encoding algorithm. One of the most intriguing aspects of Fibre Channel, this algorithm deserves careful treatment and it gets it here.

On the other hand, some topics seem to be glossed over a bit, notably the application of higher level protocols (like IP and SCSI) to Fibre Channel. Fibre Channel by itself is only part of the story. It's the application of higher level protocols to it that is so fascinating, yet these topics don't get much coverage here. To be fair, at the time the book was published, there weren't a lot of implementations of higher level protocols.

Benner often gets mired in some of the more detailed aspects of the protocol, and often he takes the reader with him. However, given the detail and complexity necessary to explain what's going on, this is almost inevitable. One can't blame the author for not making this material light and lively. At the same time, though, there is information I was looking for that I failed to extract from the text. Whether this is due to my inattention, the ponderousness of the text, or the absence of data, I can't say. Unfortunate, yes, but almost unavoidable.

Fibre Channel was brand new when the book was issued, and some trends and differences have emerged during that time. This is not the author's fault, and these changes occur most often in the application of Fibre Channel, which isn't given much coverage in this book in any case.

A final complaint might be that the book does not provide easy access for the uninitiated. However, the book does not promise to be an introductory text on general networking, so the reader can't fairly expect this.

If the reader is curious to understand this interesting technology but does not need or want to understand the whole thing, I recommend reading the first and second chapters, and then picking and choosing sections after that. Make sure this tour includes the 8B/10B encoding algorithm, a scan of FC-AL, the coverage of FC-4, and the future possibilities for FC-PH-2.

I really like the layout of the book. It allows one to get an overview of the protocol without having to wade through all the fine details. At the same time, the writing is serviceable, if uninspiring. If the topic of the book is interesting, feel free to check it out. Especially since it's about the only book on the topic in print.


Although it's not for the novice, the structure of the book allows one familiar with networking protocols who wants to get the gist of Fibre Channel to do so with no more than the minimum required investment of effort. The writing is clear enough to not interfere with the description of the protocol, although a detailed understanding will require the investment of some significant time and energy.

Click here to return to the index of reviews.