Cisco Internetwork Troubleshooting

This book is outstanding - although it is not very obvious when you first glance through it - probably the not so impressive diagrams, and the first two or three relatively ordinary chapters help build this impression. No one can ever developed any form of passion for those SHOW and DEBUG commands - but if you shift gear a bit in your mind - knowing that eventually it is very very useful - making you the Ace Ventura of Cisco Internetwork - you might actually like it.The topics cover in this book is more or less similar to the Cisco CIT course - but the details and approach is significantly different: (A)many unheard of new or not commonly known facts, tips and tricks, have been brought out - MTU size exceed 1600 causing slow response; an undocumented command SHOW INTERFACE STATISTICS; if you set ipx gns response to more than 500 ms, OS/2 workstation might have trouble getting a connection to an IPX network; ever wonder why people do not set passive interface in EIGRP and OSPF environment? Sometimes you need to modify ISDN SPID number to get it to work; (B)there are things that only this author appears to noticed and point out in SHOW or DEBUG output - like you got many more carrier transition on ISDN B-channel 2 because the line keeps closing down due to low volume traffic. (C)the author always appears to know a bit more than other - e.g. many knows that there are 4 types of Novell encap, but Cormac point out that there are 5 types and you can only use 3 types on FDDI, 2 types on token ring, and 4 types on Ethernet - looks like other author forgot that there are still token ring and FDDI network out there. Plus one additional type hdlc. (D)when examine possible cause of a unreachability - the author goes further than just router, link, or route failure, into distribution list, route-map, and other less common possibility that other authors does not examine. (E)when going through troubleshooting examples and scenario, he emphasis on using SHOW and DEBUG to detect the problem instead of just gone through the configuration and point out the mismatch or mis-configuration. I think this approach is invaluable - instead of giving you a proper map to walk through the forest, you are dump into the forest with minimal info and you see how he worked his way out. (F)Troubleshooting routing protocol is given 2 long chapters - and is probably also the toughest chapters in the whole book. This is very different from other CIT/Support book where troubleshooting routing protocols received a weak treatment. The main thing about this book is - troubleshooting is shift up at least two gear - and it really tax your mental strength.Anything no good enough? Yes: (A)The diagram could be improved greatly - the author uses black rectangular box which look like desktop PC to represent router, thick 'Z' kind of line to represent WAN link, and an iron bar that looks even bigger than the router to represent Ethernet - making the whole network looks less than convincing. (B)I

I used this book along with three others to prepare for CIT, and as the exam drew near, I found myself using this one almost exclusively.I thought the book did an excellent job explaining and illustrating the concepts. There is an excellent balance of command syntax explanation, screen output text, and explanatory text. Significant portions of command output are highlighted and explained clearly and thoroughly.I also welcomed the amount of detail, which came in handy on the exam and in real life. Details such as the breakdown of frames in different protocols are left out of a lot of study guides, but that's the kind of information I want. It's better to present the information to the reader and let the reader decide to what level he/she needs to go, rather than the author deciding what the reader needs to know. The appendixes were also thorough in their presentation of the material. Don't skip them.I also liked the question format for most of the chapters, although for most chapters there weren't that many of them. There is one section that simply presents screen readout and challenges you to find the problems. That's the kind of question you need to be able to answer to pass CIT. If you are looking for "A-B-C-D" questions, you won't find them here. You're challenged to come up with commands that perform certain tasks, which is what you need to be able to do in the first place. I would strongly recommend using more than one text for this exam (and for all Cisco exams), but if you use only one book, it really should be this one.

I studied the book for two weeks and passed the exam - albeit with quite a bit of real world experience. All the same, the book has some great items for explaining debugs and show commands and I walked away with more knowledge than I had prior to reading it.I've used it several times since to refer back to on items like "what does this counter do again" sort of stuff.

I used this book as my primary source of study for the CIT examination. The material is presented in a structered manner. The topics build upon each other as your knowledge increases. Review questions ensure that the information was retained, since they are very vague! We know for a fact the reason Cisco tests are difficult is because they never ask a direct question. I would also recommend "Internetworking Troubleshooting Handbook" isbn: 1-57870-024-8 to enhance your troubleshooting technique.

I found the techniques discussed in the book accurate. Working as a Customer Support Engineer I encounter unusual networking problems. By asking questions such as; When did the problem first occur? How long was it operational? Did anything change in your environment? Is this a different version of IOS? Did a CCNP or CCIE build your network? Questions such as these along with other troubleshooting techniques like... Can you ping the server? Is there a route in the routing table? A traceroute from the client station to the location your attempting to reach displays what? If a static route is placed from source to destination, destination to source can you ping the site? (routing problem) What language does the protocol speak? (Meaning is it routed, distance vector, link state or path vector) What about NBMA networks, Point to Point connection oriented versus connectionless (Does the protocol use TCP as transport? such as BGP port 179?) These type of solutions are provided in this book. There is a world of difference when a CCIE writes a book opposed to a amateur. If you were learning to play basketball would you want Michael Jordan or Kurt Rambis to teach you? Well this book is the Jordan of Technology books. I don't work for Cisco but a Gold Partner, and believe this book could save you from embarrassing moments. We have had clients come to us because their IS department had no clue where to start. To be honest 70% of the problems are resolved by asking the right questions. A knowledgable person knows that the DLCI only has local significance. If you see LMI you are most likely okay from end to end on the circuit. Why two stations are on the same ethernet and one can't reach the server. Before your office lost power the router's routing table had routes to all remote locations. When power was restored the router re-booted for some reason you can't reach all of the locations. (You think the CCIE was here last week and adding those locations everything should work fine! sounds like a wr mem was missing after everything was complete) Not to ramble on about things, but if you understand what I mean maybe you don't need this book proceed to Caslow's Bridges, Routers, & Switches. But if you don't know where to begin when a problem occurs, and you troubleshoot by throwing darts (I mean let's try this or maybe that, hmmm maybe this, you have no techniques). Hope you enjoy this book as much as I did and kudos to Laura for editing such a informative book!