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This tip is the first in a four-part series on things network engineers need to know to be effective. For the moment, we're going to focus on the obvious: technology. Maybe not so obvious for newcomers to the field is the fact that many aspects of technology are required to build and maintain computer networks effectively. We will approach this overview in the order in which knowledge about networking technology is generally acquired.

Frameworks

First is an understanding of networking

frameworks. There's a reason almost every networking book and class starts with a discussion of the OSI 7-layer reference model. In order to understand networking components, you have to understand the functions the components are expected to perform, and this is defined by the model. In other words, the model is the context in which the components operate. For instance, Token Ring, IPX and SPX, or Ethernet, IP and TCP are series of protocols that perform specific functions, and no one protocol can operate in a vacuum. They work only in conjunction with many other protocols which, taken together, form a system.

So, an understanding of the framework allows you to skip to the steep part of the learning curve when you deal with new technology, which will be a constant in your career. There will always be new protocols and new systems to learn and implement and support, but if you know the model, then you already have a good guess about how things work.

Frameworks defined The illustrated OSI reference model Token Ring Ethernet IP (Internet Protocol) TCP (Transmission Control Protocol)

A good source for studying these frameworks is a college textbook or a generic (not vendor-specific) networking primer. [You can also get started by checking out the resources in the Introduction to Networking section of this site. -- Editor]

Standards

The next area of technology for the engineer to focus on is standards. There is a truly vast array of networking standards today, along with several competing standards-setting bodies, such as the IEEE, IETF and ISO. These standards make an effort to provide compatibility. The effective engineer will need a working knowledge of hundreds of standards, from H.323 to IEEE 802.11a/b/g to RFC 1918.

A "working knowledge" means understanding where the standard fits in the model -- what its job is:

• what services it relies on
• what services it provides
• what constraints it imposes
• what advantages and disadvantages it has over competing standards
• what other protocols you have to configure with it

Getting started on standards 802.xx Fast Reference Where can I learn some of the basics of VoIP, like H.323 and SIP? The ITEF's RFC index page The OpenH323Project provides a guide to H.323 standards

While you're prioritizing your list of standards to learn, remember to observe where the standard in question is in its maturity cycle. Some are foundational -- Ethernet, for example -- and you just can't live without them. Others, such as VoIP, are relatively new, and though fraught with risk, fetch high salaries for engineers who are proficient with them. Still others are depreciated, like RIPv1, meaning another standard has replaced them, although that doesn't mean you won't encounter them.

If you're just starting out or looking to invest in yourself, visit your favorite Internet job board and sort the jobs by their posted compensation. Make a note of all the technologies listed in the ads for the highest-paid jobs and learn those technologies first. The technologies may be complex, but deciding where to start is not.

Products

The next thing an engineer needs to understand is that all those standards he just learned are largely academic. Vendors design their products differently, and the implementations of the same standard by two separate vendors may be quite a bit different, even if they are still interoperable.

For starters, the options available, the mechanism by which you configure them, and the terms they use to describe them may all be different. More serious is vendors' adoption of an "embrace and extend" approach to standards, which usually results in spiffy -- but proprietary -- new features and may make them incompatible with anyone else's products.

It is therefore important for an effective engineer to know not only the standard but also how the vendor implements that standard, to include: what hardware platforms it's supported on, how it might have changed since the last software version, what the known bugs are, and what sort of design quirks might cause the technology to perform better or worse.

Of course, some of these things are learned only through experience and aren't formally documented anywhere. But a good way to get most of this knowledge, at least for moderately mature technologies, is to pursue certifications. Some employers value certain vendor certifications more than others, and some certifications are more indicative of the ability to memorize than of experience and competence. However, both those complaints miss the more important point that the exam questions themselves almost always point to the elements the vendor thinks are most important for successful implementations, and to trouble spots that were encountered and resolved in the early days of the subject technology. Thus, taking a vendor's exams for a given technology is likely to show you the danger areas you want to make sure you understand before you deploy that technology.

The combination of a decent textbook, some quality time with various specifications, and the study materials for an exam will put you well on your way to mastering the networking technology of your choice.

About the author:
Tom Lancaster, CCIE# 8829 CNX# 1105, is a consultant with 15 years of experience in the networking industry. He is co-author of several books on networking, most recently, CCSPTM: Secure PIX and Secure VPN Study Guide, published by Sybex.

This was first published in August 2006