Troubleshooting Campus Networks: Practical Analysis of Cisco and LAN Protocols, by Priscilla Oppenheimer and Joseph
Bardwell, Wiley, 2002
It is perhaps rare that a book review would encompass the acknowledgements. A break from tradition here is warranted, though,
because both authors reveal up front what every prospective reader should know when faced with a purchase decision: Is this work
drawn merely from professional circumstance on the part of the author or does it embody a passion held by the author? Judge for
yourself. How often do the words "love," "wonderful," and "protocol analysis" congregate?
Coauthors Priscilla Oppenheimer and Joseph Bardwell consider the spectrum of protocols and technologies likely to be encountered in
a campus environment. A campus network, it is said by the authors, is any one that spans buildings (whether or not in an
educational setting). Of course, bricks and mortar are functionally transparent to most modern technologies, and thus the
definition of campus could easily be narrowed to any collection of departments or perhaps even any collection of LANs. A contrast
is simply being made against the larger metropolitan or wide-area arena.
Although this book does include substantial theory and background for context, it is not yet another rehash of how things
ought to behave in the vacuum of a lab environment (indeed, the authors occasionally express surprise at their own
observations). Neither is it a step-by-step troubleshooting checklist for novice network administrators. To generalize the format,
a thorough decomposition of the whole into its many parts follows an introductory discussion of the subject protocol or technology.
It is next released into the wild and is quietly observed. Some conclusions are then drawn (some by the authors, some by the
reader) regarding appropriate and inappropriate behavior. Lastly, possible courses of action in response to poor or abnormal
performance or behavior are considered. This, again, is merely a generalization. The authors take great care to keep the discussion
interesting and relevant, often doing so by sharing real-world experiences.
The six pages that comprise chapter 1 seek to set a stage, define a scope, and target an audience. The reviewer would add only that
those of us who trade in wide-area networks also stand to gain a great deal from the experience.
If chapter 2 were packaged for individual sale, it would find its way under the Christmas tree of every colleague, customer, and
boss this reviewer has ever encountered. Those readers familiar with Ms. Oppenheimer's acclaimed Top-Down Network Design
[1] may be surprised to find the expression "bottom-up" in any of her work. It is, however, cornerstone not only to the chapter,
but also to the remainder of the book.
This seemingly obvious approach to trouble-shooting and analysis could not possibly be emphasized enough according to this
reviewer's professional observation.
Chapters 3, 5, and 6 delve into campus datalink layer technologies, protocols, and architectures, including Ethernet,
Spanning-Tree Protocol (STP), and Virtual Local-Area Networks (VLANs). Yawn? The reviewer challenges the reader
to finish these three chapters without learning something of considerable value. The Ethernet discussion, for example, breaks from
the traditional approach where a cursory review of frame types, cable types, and topologies is deemed sufficient. Where Ethernet
came from, where it is going, how it is encoded and presented to the physical layer (and why), and how to interpret frame size
distribution using Remote Monitoring (RMON) or a protocol analyzer are but a few of the topics considered. Extensive use
of protocol analyzer capture files casts new light on STP and VLANs.
Chapter 4 additionally addresses a Layer 2 technology (IEEE 802.11 wireless LANs) but warrants honorable mention. Rare is the
radio frequency (RF) engineer who possesses a full appreciation for the heretofore all-digital, all-wired campus realm.
Perhaps less common would be the network administrator with a capacity to do much other than tune in an FM radio station on a
digital set. The authors masterfully string together all the relevant RF concepts, at exactly the right level of detail, to allow
for a solid fundamental comprehension of 802.11 networks, technologies, architectures, and deployment. This chapter also would do
superbly for anyone with a generic interest in RF units of measurement.
Chapter 7 advances the discussion up to the network layer. Although this may seem common knowledge for readers of a publication
such as the IPJ, it is written from the perspective of seasoned protocol analysts. It is worth your time.
Chapter 8 persists at Layer 3 with a thorough discussion of relevant routing protocols. It is again worth noting the emphasis on
analysis versus simple textbook theory. It, too, is worthy of your investment.
Chapter 9 rounds out the protocol stack, beginning with an emphasis on Layer 4 protocols Transmission Control Protocol
(TCP) and User Datagram Protocol (UDP). One of the highlights found here is a thorough lesson on TCP window size analysis.
Could there perhaps be a little more to this seemingly intuitive concept than you at first thought? The chapter closes following an
in-depth consideration of application layer protocols such as the File Transfer Protocol (FTP), Hypertext Transfer
Protocol (HTTP), and the Domain Name System (DNS). The fundamental mechanics of these protocols and how they interact
with their lower-layer counterparts make for a good page-turner.
Chapters 10, 11, and 12 are dedicated to troubleshooting and analysis of Internetwork Packet Exchange (IPX), AppleTalk,
and Windows networking, respectively. The latter is arguably the more relevant. The other two are nonetheless interesting and left
the reviewer longing for a decent AppleTalk trace file with which to recreate.
Chapter 13, WAN Troubleshooting for LAN Engineers, covers the obvious wide-area technologies and architectures, such as
Integrated Services Digital Network (ISDN), Frame Relay, and Synchronous Optical Network (SONET) in about as much
detail as the typical LAN engineer or administrator is likely to tolerate. The subject of WAN analysis warrants a volume or two on
its own in any case and thus would have been out of place if explored in much greater detail.
The reading of Troubleshooting Campus Networks is not to be approached as a spectator sport. Although the protocol analyzer screen
captures are aplenty, and they suitably complement the lessons, merely thumbing the pages would be an opportunity missed. This
reviewer chose a free, open-source protocol analyzer (readily available on the Internet) as a reading companion. Although likely
far less capable, particularly in terms of graphing, than the oft-referenced Wildpackets EtherPeek product, it nevertheless affords
the reader a Layer 2 through 7 window into a living, breathing network.
It bears mentioning that although "Cisco" appears in the subtitle, vendor neutrality is, on the whole, maintained. The Cisco
sanctioned troubleshooting methodology is given brief mention in chapter 2. Coverage of the Cisco proprietary Interior Gateway
Routing Protocol (IGRP), the Enhanced IGRP (EIGRP), and the Cisco Discovery Protocol is included, as is coverage of Cisco's
"enhancements" to STP. Lastly, where appropriate, Cisco IOS® "show" and "debug" output is included alongside protocol analyzer
screen captures. None of this coverage appears to be included in the spirit of product promotion (bear in mind that this is not a
Cisco Press title and that neither author is presently employed by Cisco Systems). Rather, it seems simply to be an acknowledgement
that the target audience might very well include candidates for Cisco's professional and expert-level certification programs (and
rightly so).
It is probably anticlimactic that the reviewer would offer a strong buy recommendation for those with an interest in the
fundamental interworkings of campus protocols and technologies. The authors' enthusiasm for packet capture and analysis is
infectious. Mr. Bardwell, in fact, is apparently so infatuated that he is at times moved to poetry. This could well be one for the
ages.
[1] Top-Down Network Design, Priscilla Oppenheimer, ISBN 1578700698, Cisco Press, 1998.