T1: A Survival Guide
||Author: Matthew Gast|
List Price: $29.95
Our Price: Click to see the latest and low price
Publisher: O'Reilly & Associates (15 September, 2001)
Sales Rank: 76,934
Average Customer Rating: 4.33 out of 5
Customer ReviewsRating: 3 out of 5
What a great age we live in, where you can teach YOURSELF your entire profession! As a self-taught network engineer, I have great respect for some of today's tech writers who have single handedly taught me TCP/IP, Ethernet, Cisco routers, and Linux! The only aspect of my job for which I have had to rely solely on experience, (and the meager amount of information on the web) is T1s and synchronous circuits/leased lines. As far as I know, the only books which discussed the technical details of T1 and synchronous circuits are general telecommuncations text books. None are written from a contemporary network administrator's point of view. So, you understand my excitement at seeing O'Reilly take a stab at just such a book!
The book starts off at a good pace, talking about the history of the telephone network and its evolution into the digital age (the reason we have T1 available as a data service). It discusses the different terminology related to T1's, and the equipment that connects them to our routers, but makes very few analogies or examples to solidify the relationship of these terms to each other or to the big picture of networking. After discussing the physical and logical layout of T1 and its physical interface with our routers, Gast spends the next 40 pages on the nitty gritty details of T1: Timing, Framing, Coding, and the lights on the CSU/DSU. All the important aspects of T1 are discussed in a logical order. Unfortunately, it's not enough; Gast breezes through the most important and mysterious aspects of T1 without so much as one good analogy or explanation to develop the ideas. The diagrams are equally disappointing. They have a lot of information, but do little to clarify the subject matter. The T1 framing sections, especially did not get enough attention. This is the heart of T1, and really wasn't explained well enough.
After getting what seemed to be an introduction to the subject matter, I expected the rest of the book to go into further detail about the intricacies of T1 framing and coding, and ways to hash out possible problems on T1 circuits. Instead, the next 60 pages give the boring and useless details of the three most common link-layer protocols run over T1s: HDLC, PPP, and Frame Relay. Gast continues to litter the pages with confusing and uninformative diagrams, and then spends time explaining the details of each one step-by-step. Good diagrams don't need step-by-step explanation; they speak for themselves!
The level of detail he goes into for each of these protocols is similar to what you might find in a general Data Networking text. He discusses different principles of data communication as well as the specific frame formats of these protocols, but doesn't explain how these protocols specifically interact with T1. Although he gives the frame formats of these different WAN protocols, he doesn't give enough information or suggestions on using the information in any effective way. The oversimplification of many of the diagrams makes the book less useful than the RFCs which will give you the exact frame formats.
Gast assumes that if you don't work for one of the telcos, the only way you may come across a T1 is as a small business network administrator responsible for maintaining internet access via T1. That is not the case anymore; many large companies manage their own backbone and have access to leased lines, and T1 testers. The only time a T1 tester is mentioned, it's described as 'a handheld device with lots of buttons and blinking lights on it.' The principles behind T1 testing are quickly covered, but the intricacies of testing T1s and using T1 testers are not. This is unfortunate, as many Cisco routers have built in test pattern generation and loopback capabilities! (As do most standalone CSU/DSUs.)
It's obvious, as it is in many poorly written tech books, that the author knows his subject! The problem is, he doesn't consider the fact that we, the reader, may not. The book wasn't a complete waste of time; there is a lot of good information in here. Information on signaling and different types of alarms on T1s is present. The majority of it is just not explained very well, and too much time is spent on the link-layer protocols. I probably wouldn't be so down on this book if it didn't have O'Reilly's name on it.
By the way, this is the exact review I wrote for slashdot, if it sounds familiar!
Rating: 5 out of 5
Finally - O'Reilly does T1s
Until now, it has been a difficult (impossible?) task to find a really good reference on T1s. There are plenty of books out there on digital communications, but they tend to be too general, lumping in SONET, ATM, etc. with minimal coverage on the T carrier system. Finally, in traditional O'Reilly style, we have a definitive focussed and entertaining reference book on the subject of many an IS manager's greatest nightmare. The author takes the reader on a tour of the T carrier system with clear explanations on signalling, timing, and the different components which make up the system to provide a cohesive overview of what goes on behind the scenes when that smartjack shows up in the wiring closet. Additionally, the coverage on PPP and frame relay is exceptional (if a bit brief on the frame side). Chock full of charts, tables and diagrams, the book is an excellent reference, while also serving as an entertaining introduction to the subject for the uninitiated. If you work with, plan to work with, or have ever been curious about T1s, this book should be considered required reading.
Rating: 5 out of 5
Finally, a much needed book arrives on the market
Gast's T1: A Survival Guide is a fantastic resource for networking professionals in the IP world. All too frequently we are called upon to interface with Verizon and other big carriers that speak a language that is completely foreign to our world (and they don't speak our language, either!). This book finally brings the lingo of the telco world into terms that the networking professional can quickly grasp and understand, which is something that anyone that has spent any time talking to switch and transmission techs can appreciate.
"It's blue? All 1s? MUX? DACS? Biscuit?"
Finally these terms make sense!
· Ethernet : The Definitive Guide
· Sonet and T1: Architectures for Digital Transport Networks (2nd Edition)
· Guide to T-1 Networking: How to Buy, Install & Use T-1 From Desktop to Ds-3
· Frame Relay: Technology and Practice
· Sonet/SDH Third Edition