CCIE Professional Development: Cisco Lan Switching (The Cisco Press Ccie Professional Development Series) [Hardcover]

Performance issues are addressed in the book, such as those that arise in Ethernet. The authors show how to calculate the theoretical frame rates for Ethernet, and also give advice on when to judge whether or not an Ethernet network is functioning well. That judgment will be dependent on subjective factors such as user perceptions, as well as quantitative measurements taken from the network. The authors also stress the need for being aware of the hardware limitations of the client when increasing the network bandwidth. Clients could handle a Fast Ethernet for example, and there are times when such bandwidth is needed. However a Gigabit Ethernet connection could actually slow down a typical client workstation due to software interrupts. They elaborate on the Fiber Channel technology when addressing these issues also. Also discussed are the differences between copper and fiber optic media and what kinds of configurations they are best suited for.

The authors give the reader insight into the need for LAN segmentation, and compare collision and broadcast domains. They are careful to point out the need for actually measuring the average and peak bandwidth consumed by the applications, rather than just relying on the quoted theoretical bandwidth. All of the network configurations that the authors discuss can be modeled by commercial simulation software available on the market today. This software can complement the book in that the reader can see just what can happen when making network design changes as specified in the book.

Large enterprise businesses frequently need to make use of VLANs and the authors discuss in detail the justifications for using them. These include network security and privacy, broadcast distribution, bandwidth utilization, network latency from routers, and complicated access lists. The authors though emphasize that VLANs may not be as simple to manage as some network administrators believe. The complexity of the network may in fact increase with the use of VLANs, due to the nature of the Spanning Tree algorithm and the dispersive characteristic of broadcast domains. The desire to have a "flat" network via "end-to-end" VLANs ran into issues with scalability, due mostly to the Spanning Tree algorithm.

Due to its importance, the Spanning Tree protocol is discussed in great detail in this book, with two chapters spanning 136 pages devoted to its elucidation. It is introduced as a loop-prevention protocol that allows bridges to communicate with each other with the goal of discovering physical loops in the network. An example is given of a feedback loop that resulted in 2.4Gbps of traffic in 45 minutes, in order to convince the reader of the severity of feedback loops. All of the examples discussed in these two chapters illustrate the need for great care when implementing the Spanning Tree protocol in LANs. Also discussed is the tricky task of doing Spanning Tree load balancing, which must be done if one is interested in creating a network with optimal performance. Root bridge placement, port and bridge priority, and port cost are the techniques discussed for doing Spanning Tree Load Balancing. The role of VLANs in the creation of multiple Spanning Tree domains over a single physical infrastructure is readily seen in all of these techniques. The advantages and disadvantages of each technique are summarized in detail by the authors.

Networks rarely exist in isolation, with connections between them being the norm rather than the exception. The authors therefore discuss different methods of doing the interconnection, via AIM, FDDI, or Ethernet. This is called "trunking" and is discussed in great detail in the book. As pointed out by the authors, trunking has more scalability then access links since a network administrator can distribute the VLAN connectivity without the need to use a large number of cables and interfaces. One of the most useful of trunking technologies, at least to this reviewer, is EtherChannel, which can give trunk speeds on the order of FastEthernet and Gigabit Ethernet without the need to use another technology. The authors discuss the advantages of using EtherChannel, its ability to function as both an access or a trunk link, and its ability to bundle segments so as to offer more effective bandwidth than any one of the individual links. The authors also discuss the proprietary CISCO link negotiation protocol called Dynamic Trunk Protocol, which reduces the possibility of incompatibility when links are being configured. The trunking capabilities of ATM technologies are also discussed in the context of their long-distance capabilities and their ability to carry different types of traffic, such as voice and video. For readers not familiar with ATM, the authors give a fairly detailed review of it, and an overview of Emulated LAN (ELAN), the latter of which is a special type of VLAN, namely a LAN emulated over ATM. This motivates a treatment of LANE, and then a discussion of trunking in a Catalyst environment, with Multiprotocol over ATM (MPOA).

I'm ready to get serious about my CCIE studies, and the first stop on that journey is Cisco LAN Switching. This book is on every CCIE reading list I've seen and is generally regarded as a "must have". I was prepared for some pretty heavy reading and was pleasantly surprised and pleased with this book. This isn't a book that's just for CCIE candidates, but rather it should be part of every Cisco professional's library.

I'll take you through each of the 6 sections.

Part I - Foundational Issues
The first 5 chapters of the book take the reader from the very basics of switched networking, providing a fair amount of the history and theory necessary to understand the rest of the book. Even CCNA candidates should read this section, as it explains the basic elements of switching much better than any other book. The thing that surprised me was the authors' sense of humor, which is surprisingly refreshing in a book of this size.

Part II - Spanning Tree
Ah, spanning tree. There's nothing more exciting than reading about spanning tree. This book gets it all in within 2 chapters, again providing expert explanations laced with a sense of humor. The reader is taken from the very basics through very advanced spanning tree configurations. I would have like to have seen coverage of rapid spanning tree, but hopefully it's in the works for a future edition.

Part III - Trunking
These 3 chapters, covering Ethernet trunking, LANE, and ATM, are sure to leave you a little numb. Since I've never used ATM or LANE and have no frame of reference, the material was skim-able at best. Since LANE is no longer represented on the CCIE exam, you can get away with skimming some chapters for vocabulary words.

Part IV - Advanced Features
This section covers Layer 3 switching, VTP and multicast services. A lot of this stuff is rehashed from BCMSN, but it's well explained here. There is a lot of good information on MLS and VTP, but I found that some of the gory multicast details were better explained in the BCMSN book. Chances are good, however, that most CCIE candidate readers are CCNP's and have read that book as well. By this point in the book, the sense of humor has pretty well evaporated.

Part V - Real-World Campus Design and Implementation
This section looks at a variety of network designs and the pro's and con's of each. These chapters bring together a lot of the ideas expressed throughout the book and put them into real-world situations. A lot of this is boring, but there are some tidbits and tips you can pick up along the way.

Part VI - Catalyst 6000 Technology
I was greatly anticipating the coverage of Catalyst 6500's, since there is so little published work available for this platform, which I use extensively. They only gave me 34 pages (this was obviously an add-on to the original edition of the book), but I'll take what I can get. There was a lot of good information in this section, which I'd like to see expanded in a later edition.

Conclusions
This book is widely regarded as part of the "Holy Trinity" of CCIE preparation books, standing alongside Routing TCP/IP Vols I & II by Jeff Doyle as the essential books to read when preparing for the CCIE written exam. This is for good reason. It provides an explanation of a majority of the pertinent switching technologies and also serves as an ample design and implementation guide. My only real critique is that some switching technologies from the CCIE blueprint are conspicuously missing. Hopefully, this will be corrected in an updated edition. Still, I recommend this book, not only for CCIE candidates, but also as an essential book for anyone serious about a career in networking. On my 5 ping rating scale, I give it a 5.

!!!!!

Cisco LAN Switching is broken down into 6 sections. Section 1 is concerned with foundational issues and gives an excellent introduction to bridging and switching technologies. The other sections progress through VLANS and STP to Trunking and advanced topics. Each chapter concludes with review questions and the later chapters have hands on lab configurations. The book ends with real world campus design models, implementation and case studies, which tie all the earlier sections together.

Each topic is thoroughly explained and the diagrams and definitions help clarify certain areas. I also found the tips and notes in the chapters very helpful in understanding the material better. Another interesting point is that the chapters dealing with STP were reviewed by Radia Perlman, creator of the Spanning Tree algorithm. Even without a whole lot of exposure to the spanning tree protocol, the material was presented in an easy to understand format. However there were a few issues I did have with the some of the content and the layout of the sections dealing with trunking.

The first chapter addresses the basics of LAN switching and bridging but does not go into enough depth on the different bridging technologies. I believe an expanded discussion on bridging technologies (SRB, RSRB and DLSW+) would have been helpful as well as a section on deciphering an RIF.

The section on trunking technologies goes into great depth about different types of trunking, including a wide array of diagrams and tables explaining each technology. While the subject matter is thoroughly covered, I do have an issue concerning the layout of the chapters. The authors devote an entire section of the book to trunking technologies, yet they place the chapter on VTP in an entirely different section of the book. I believe the flow of the chapters would have been more consistent if VTP was addressed in the section on trunking technologies.

These small issues aside, I found this book very helpful for my studies toward the CCIE and also in implementing better switching technologies in my company's network. I would definitely recommend this book to anyone who plans on using any type of switching in their network environment or those studying for Cisco certification. However, this book should not be used solely as a study resource and then be put aside; it should be an integral part of any network administrator's reference library.