Designing Large Scale LANs

Features

• Cover Type: Paperback with 400 pages
• Published by: O'Reilly Media, Inc.
• Edition: 1st Edition January 15, 2002
• Written in: English
• ISBN 10 Number: 0596001509
• ISBN 13 Number: 978-0596001506
• Book Dimensions: 9 x 6.9 x 0.9 inches
• Weighs: 1.3 pounds

Product Review
Large networks are complex systems, with many interdependent devices held together only by the strength of the network designer's specifications. It takes a lot of knowledge--and a lot of time--to make sure that the capacity of links and nodes is neither wasted nor overloaded. Designing Large-Scale LANs explains how the pieces of a large local area network (LAN) interoperate. A LAN, in author Kevin Dooley's working definition here, is a building-size data network, or perhaps a campus-size system with a backbone running Gigabit Ethernet, ATM, or FDDI. Dooley does a good job of teaching his readers about, for example, the processing overhead involved in address translation or protocol tunneling, and why techniques like those should be used sparingly in a LAN that requirements to be fast and efficient.

That said, Dooley spends a lot of time on network fundamentals. He explains subnet masking in his own rather appealing way, and takes readers on a tour of the Open Systems Interconnect (OSI) seven-layer model. He explains the function of split horizon and poison reverse in Routing Information Protocol (RIP), as well as the improvements more modern routing protocols make on RIP. In short, there's an awful lot of background information here. Designers of big networks need to understand this stuff, but you might expect to see comparisons of competing vendors' equipment here--there's not enough of that--and less broad, conceptual information. On the other hand, you could do far worse than to study this book in preparation for a networking certification exam. --David Wall

Topics covered: How to design a resilient, fast, and efficient local area network (LAN). Vendor-neutral to a fault, this book explains the relative merits of LAN media and topologies, and goes into detail on how to design an addressing scheme for routing efficiency. An appendix on the mathematics of combining probabilities (e.g., the probability that both this router and that switch will fail at the same time) is a nice touch.

Product Description
This unique book offers a vendor-neutral approach for designing large local area networks according to business or organizational needs, rather than from a product perspective. Author and independent network design consultant Kevin Dooley outlines "top-down network design" for building a technological infrastructure to fit your organization's requirements, a process far more effective and cost-efficient than fitting the organization to the parameters of a shrink-wrapped proprietary solution.

Dooley argues that the design of a network is largely independent of the products used. Whether you use a Cisco or Juniper router, the same security issues and protocols apply. The questions he addresses in this book are need-specific: Do I use a router or a switch? Should I route between switched areas or switch between routed areas?

"Designing Large-Scale LANs" covers everything from security, bandwidth and scalability to network reliability, which includes backup, redundancy, and points of failure. Specific technologies are analyzed in detail: network topologies, routing and switching strategies, wireless, virtual LANs, firewalls and gateways, security, Internet protocols, bandwidth, and multicast services. The book also discusses proprietary technologies that are ubiquitous, such as Cisco's IOS and Novell's IPX.

This complete guide to top-down network design will help you choose the right network solutions. If you're designing large scale networks and need expert advice and guidance, look no further than "Designing Large-Scale LANs,"

Reader Reviews
Review of Designing Large Scale LANS, by Kevin Dooley Good book! This is what the title implies: a book about designing large networks. It's not primarily an implementation book. It treats its subject rigorously, but without tons of detail at the end points. For example, you won't find cat5e pinouts discussed. You will see a redundant, heirarchical network design. I like a book with real math as , and the author actually provides some for aggregate Meant Time Between Failure (MTBF) calculations. Stats and probability! Cool! He gives less rigorous but useful rules of thumb for capacity planning. Lot's of advice reflecting his extensive real-world experience. Like the importance of physically redundant trunk links (rather than just two circuits in the same fiber bundle|conduit). My impression was that stuff never failed unless a backhoe severed it, but I was...incorrect. Thanks! I will be working on a plan to get redundant links in place. I had an intuitive sense that there is a trade-off between redundancy and complexity. Reliability is the goal, and you can add features (primarily redundant circuits and components) to a point where the complexity reduces reliability. Dooley gives a fairly clear impression of where the trade off is profitable. The VLAN treatment is extensive. Again, I knew that trunking all VLANS on the campus net across all trunks was wasteful; he quantifies it. Overall, the book stands up well after 4 years. He doesn't spend much more than a sentence or two on wildly obsolete media like 10Base2 (coax). There's the occasional PanAm moment (the shuttle taken to the space station in the movie "2001" is operated by PanAm) like when he refers to Compaq as a manufacturer of network interface cards. I still see issues with 10BaseT and probably you do too, so I don't begrudge him any space on the topic. He was forward thinking enough to mention gigabit ethernet. He refers to Cat6 cable as a future standard. He cautions against using intermediate patch panels, which I was given to understand are o.k. One major building on our campus uses them, at the behest of the wiring designer. Oops. I haven't noticed any problems, but now I know to look. Wireless is the area where change has been fastest, I think. Probably something to do with inexpensive, commodity hardware (with broken initial specs) leading to faster refresh rates. He mentions (back in 2002, I remind you) the utter brokenness of the WEP encryption standard. But if wireless in detail is your thing, this is not your book. There isn't much on different types of fiber optic cable. (not in book - this is my own accretion of data) What I know of is: single-mode on the 9nm wavelength, which goes from 10km to 80km depending on the fiber transceivers. Multi-mode is in 50nm (newer(?) better distance|speeds) and 62.5nm (more common) The IP routing/subnetting stuff is good. QoS treatment is good: he shows why you can't just throw bandwidth at a problem to give good video|voice. Variable latency (called "jitter") makes it hard for voice|video apps to buffer, leading to pops and crackle that drive users up a tree. Of the three approaches, he recommends only Guaranteed Delivery will suffice. Multicast treatment is good. I have never had a handle on that stuff. Now I do. Some good operational details - in the network monitoring section, he urges us to monitor even quiet backup links. If the backup failed and nobody noticed, they will when the primary dies. In sum, this book is worth the time to read it. It's a little old, but the stuff that is essential to its topic has not changed. Heck, the age just means you can get it dirt cheap. Check ebay or amazon used. Even with list price books, the real cost is the time to read them. This one should reward someone growing into the network engineering role. Being able to grab a copy for $5 plus shipping is just gravy. Comment | | (Report this)