Wednesday, June 13, 2007

Deploying an enterprise network or How to save yourself from sabotaging yourself

So you have taken the plunge- looked at the budget, fielded questions and requests from employees, huddled in conference rooms looking at the one wired computer- and decided that your office or campus could really use a wireless network. So you talk to your Cisco representative and let him know that you are ready to buy some controllers and access points. He or She happily takes your order, shakes your hand, jokingly suggests a dinner, and skips out the door.

Congratulations! You are now the proud owner of a wireless network- soon your employees will be surfing the web, convening for impromptu conferences without worrying if there is a jack to plug into, and interacting more with each other. However there is still lots of work to be done- not necessarily by you, but work nonetheless. It is time for a site survey.

The step is critical yet overlooked by most companies. They simply think you can take an AP out of the box, plug it into the ceiling or wall, and everything will work well. If coverage is spotty, you just take another AP and voila! problem solved. Alas, nothing could be further from the truth. While Wireless Control System (WCS) and other management tools have made it easier to see trouble in the network and Cisco's Auto RF does allow for the network to self-correct, it does not replace the need for a site survey. Many companies try to insist that with their product they have eliminated the need for a site survey, but it is much more than channel assignments and making sure you have an access point outside the boss' office.

I always recommend a good, professional site survey. This is not some co-worker walking around with a laptop scanning for possible signals from Starbucks, the apartment complex across the street, or the one you have hidden under your desk because you at least deserved wireless even if the CIO didn't see it that way. A site survey should start with you contacting a partner who is knowledgable about RF and has dedicated himself to surveying locations and installing APs. These people are not cheap (usually around $5,000-$10,000+), but they will usually guarrantee their work and will make the necessary adjustments and calculations to achieve the best coverage. They use sophisticated equipment to look at the enivronment, taking everything into consideration including usage patterns, worker habits and business practices, and possible interference (like that pesky microwave in the break room). A good survey will usually take a few days to complete and at the end the installer should hand you something close to a book report on what your environment looks like and antenna recommendations and so on. There is a lot of information you can get. Surveyors will also mark off where APs should be placed, possible channel assignments (though most will let the network determine the channel to set it to) and other factors no one takes into consideration.

I know what you are thinking- that seems like a lot of money to spend for a guy to tell me that information. Nothing could be further from the truth. These are the people who will actually get your wireless network to run. Once the network is deployed and you start seeing coverage issues or problems, it is already too late to make major adjustments (and considerably more expensive). I am constantly visiting customer sites where they simply took an AP and placed them around the building and are starting to have issues ranging from coverage, interference, bandwidth, and placement. When I walk in, the first thing I usually ask is if they did a site survey. If they have, then I can look at the plan that the sureyor put together and see what happened. This happens 1% of the time. The other 99% of the time I get a blank look and a mumbled answer of "I used Airmagnet." Those 99% always have network problems because they don't know what to look for when planning the network. There truly is a lot to think about. The people who do a site survey have great wireless networks because they took the time, resources, and energy to do everything properly.

Allow me to leave you with this example. When you buy a car, you don't just go to the dealer and pick up the car without asking questions and then worry about problems as they come up (if you do, I have a car that is perfect for you). Instead, you do research, perhaps buy some consumer reports, consult with other people, and even figure out pricing and options you want so that when you walk into the dealership you have all the information you need to buy the car. But that's not all. The crucial step is that you also take the car out for a test drive. You have all this information about the car, but you haven't sat behind the wheel and pressed on the gas. And when you do the test drive, you don't just take it around the dealership parking lot and make a decision. You take it on the road, open it up on regular streets, and see how it performs under regular conditions. It is like you are site surveying your car. Skip that step and you have no idea if your car is going to perform as you would like it to. Skip a site survey and you will end up with a wireless network that belongs in the junk heap as well.

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