The unified network arrives

Combining wired and wireless networks

One of the core problems with wireless networks way back in the late 1980s and early '90s was a serious lack of throughput. Wide-area wireless networks provided paltry speeds of between 2.4Kbit/sec. to 4.8Kbit/sec., and effective WLAN throughput was well under 1Mbit/sec.

As a consequence, I often wrote in those days that wireless was most suitable to augment wire but that it would not replace wire anytime soon. That assessment was accurate until about five years ago, when it became clear that advances in radio technology would eventually provide something close to parity in performance from a throughput, if not a time-boundedness, perspective.

This, in turn, has led me to say something that I never thought I would: In some cases, at least, wireless will, in fact, replace wire. Cell phones are an excellent example of how this is coming true. Perhaps 20 percent of users today have made their cell phone their primary or, sometimes, their only phone. That's particularly true with teenagers and twentysomethings who grew up with wireless and have made it an essential element of their lives and culture.

We are now seeing a similar phenomenon with enterprise-class WLANs. It is very difficult to buy a notebook computer that doesn't have built-in wireless, and Wi-Fi radios are starting to appear in enterprise-class cell phones as well. I now see wireless rapidly becoming the default access method in virtually all industries. IT departments are becoming satisfied that we've addressed core reliability, security, cost, management and operations issues. Cisco recently told me that they have installations involving between 50,000 and 60,000 access points in mission-critical environments around the world. Default, indeed!

So, as I was recently asked, does this mean that wire is doomed? Will enterprises go entirely wireless? Should we even bother installing new wire at all?

The answers to those questions are an emphatic no, no and yes. In gross terms, wireless has the convenience factor going for it and its price/performance has been dramatically improving. But wireless still suffers, and always will, from both radio artifacts like fading, which results in highly variable performance, and interference, which I've covered in great detail in a past column.

Wire, on the other hand, has the undeniable benefit of what I call bandwidth multiplication. Need more capacity? Just install more wire or cable or fiber. Unlike wireless, which uses one big wire in the sky, each wire is its own nice, neat little electromagnetic world. Interference? Not likely, especially with fiber. Of course, mobility is not an option with wire, which works only in stationary applications. However, there are still lots of these applications in places such as accounting departments, call centers, help desks, servers, printers and NAS.

And, while gigabit Ethernet is simple and cheap, we won't have gigabit wireless LANs for a while yet even most 802.11n products will yield only a small fraction of that number. So, when maximum throughput is a requirement, wire still is the only option.

My advice, then, is to always use wire where you can and use wireless only when wire cannot be installed because of costs or physical restrictions, or when mobility is a factor.

But this leads to yet another, and very important, conclusion. Since we need both wire and wireless, we must stop thinking in terms of wired and wireless networks and begin the journey to the era of unified LANs. A unified LAN is just that wired and wireless working together, interdependently and cooperatively.

Wire, after all, is typically how access points are interconnected, along with wireless controllers and location appliances. Network planning needs to design in the capacity to handle both wired and wireless users, devices and core equipment. There are real total-cost-of-ownership benefits to this approach as well.

The ultimate goal of unification, to my way of thinking, is having a single management capability that controls both domains. There is enormous commonality in management functionality, especially with respect to policy, user administration and security, so the duplication of these functions makes little sense. Unified LANs, I believe, will become the best tool for the job over the next few years, and now is the time to begin planning for this eventuality.

So, do you have a unified LAN in your future? It's a safe bet that you do, no matter how large, or small, your company is.

Craig J. Mathias is a principal with Farpoint Group, an advisory firm specializing in wireless networking and mobile computing. He can be reached at craig@farpointgroup.com.

Copyright © 2007 IDG Communications, Inc.

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