Troubleshooting Campus Networks
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
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
 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,
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
(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
(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
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
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
(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.
IT Artisans Group
IT Artisans Group
Top-Down Network Design
, Priscilla Oppenheimer, ISBN 1578700698, Cisco Press, 1998.