T1: A Survival Guide [Paperback]

Matthew Gast (Author)

Book Description

ISBN-10: 0596001274 | ISBN-13: 978-0596001278 | Publication Date: September 15, 2001 | Edition: 1st

If you haven't worked with T1 before, you could be in for an unpleasant surprise. If you have, you'll already know that T1, the current network standard for business and professional Internet access, is neither efficient, easy to use, nor particularly well-suited to data transmission. T1: A Survival Guide, a practical, applied reference on T1 data transport, is a life raft for navigating the shoals of a 40-year-old technology originally designed for AT&T's voice network.

Throughout T1's long life, network administrators have mainly learned it by apprenticeship, stumbling on troubleshooting tidbits and filing them away until they were needed again. This book brings together in one reference the information you need to set up, test, and troubleshoot T1. T1: A Survival Guide covers the following broad topics:

• What components are needed to build a T1 line, and how those components interact to transmit data effectively
• How to use standardized link layer protocols to adapt the T1 physical layer to work with data networks
• How to troubleshoot problems and work with the telephone company, equipment manufacturers, and Internet service providers

In spite of its limitations, T1 is a proven, reliable technology that currently meets the need for medium-speed, high reliability Internet access by institutions of many sizes, and it's likely to be around for a while. T1: A Survival Guide will take the guesswork out of using T1 as a data transport.

Editorial Reviews

Amazon.com Review

The T1 line and its predecessors were developed as long-distance voice trunks, but now they're used almost exclusively as data connections for large and mid-sized organizations. In part because they've been adapted to fill a new role, T1 lines make use of complicated signaling and linking protocols. What's more, T1 technology has a lot to do with the public telephone network, which means most router jockeys and other "data people" lack the background they need to speak intelligently with engineers at T1 providers. T1: A Survival Guide explains leased T1 data circuits for the benefit of the lessee--in other words, for the telephone company's customer. The book is also useful for telco people who want to understand where their clients are coming from when they ask "elementary" questions.

The truth be told, this book probably won't enable organizational network administrators to fix any but the most basic problems with their T1 lines and the Customer Premises Equipment (CPE) associated with them. It is nonetheless a worthwhile read. Matthew Gast, who works on the ever-blurring border between voice and data as an engineer at Nokia, explains how a Channel Service Unit/Data Service Unit (CSU/DSU) works and provides a ton of information about the protocols that communicate data over T1 links (including HDLC, Cisco-enhanced HDLC, PPP, and Frame Relay). Lots and lots of bit diagrams, signal tables, and pictorial representations of networks clarify T1 as much as possible. --David Wall

Topics covered: The T1 line as a high-capacity carrier of digital data, with coverage of multiplexing and other aspects of T1 architecture, as well as High Level Data Link Control Protocol (HDLC), Point-to-Point Protocol (PPP), and Frame Relay. There's excellent coverage of how to order a T1 from a telephone company (as well as how to figure out if you need more than one), and a guide to working with telco engineers during install and troubleshooting.

About the Author

Matthew Gast currently works for an advanced wireless network systems company in the Bay Area. Prior to that, he spent several years as an engineer for a series of network security companies. He is the author of 802.11 Wireless Networks: The Definitive Guide, Network Printing, and T1: A Survival Guide.

Product Details

• Paperback: 128 pages
• Publisher: O'Reilly Media; 1st edition (September 15, 2001)
• Language: English
• ISBN-10: 0596001274
• ISBN-13: 978-0596001278
• Product Dimensions: 9.2 x 7.1 x 0.7 inches
• Shipping Weight: 1.1 pounds (View shipping rates and policies)
• Average Customer Review: 4.5 out of 5 stars  See all reviews (6 customer reviews)
• Amazon Best Sellers Rank: #256,895 in Books (See Top 100 in Books)

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Customer Reviews

Most Helpful Customer Reviews

9 of 9 people found the following review helpful:

5.0 out of 5 stars Finally, a much needed book arrives on the market, October 10, 2001

By 

Charlotte Oliver (Washington D.C.) - See all my reviews

This review is from: T1: A Survival Guide (Paperback)

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!

10 of 12 people found the following review helpful:

3.0 out of 5 stars Mediocre reference..., July 24, 2002

By 

Mark Twain (Sydney, Australia) - See all my reviews

This review is from: T1: A Survival Guide (Paperback)

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!

4 of 4 people found the following review helpful:

5.0 out of 5 stars Invaluable T1 reference, December 11, 2004

By 

Jeff Roback (Los Angeles, California United States) - See all my reviews

This review is from: T1: A Survival Guide (Paperback)

This book is an invaluable reference to the art and science of T1 lines. If you're in a position where you regularly install or troubleshoot T1 lines, this book will make you infinitely more successfully at your job.

The book puts many topics under 1 cover, including the physical wiring of T1 jacks, the configuration options needed when ordering, as well as the methodlogy used by the telephone company to troubleshoot malfunctioning lines. Unlike many telecommunications references, this book is written focusing on the practical aspects of installing, troublehsooting, and monitoring t1 jacks. There's sufficient background material to explain how things work, but it focuses on the practical, making it a much quicker read.

By understanding the language and concepts of T1 lines you'll be able to much more effectively troubleshoot T1 activity and interact with the telco. Even if you don't work with these on a daily basis but are just curious, the book is well written enough that it makes for an interesting read.