Why Wireless Design is Essential in the Enterprise

 25 Jan 2007 11:05:08 pm

The past year wireless has gradually become the piece of technology I deal with more than anything else. Most of my time is spent in the large to enterprise environments with Cisco’s centralized architecture (formerly AireSpace). A portion of the increase is new wireless deployments; however the majority of it is organizations trying to replace or repair their existing wireless infrastructure because they don’t meet the current needs or has large problems that cannot solve internally.

My (brief) take on the evolution of LANs throughout the years. Once upon a time LANs were small, slow, expensive, used a shared medium, built ad-hoc and to serve a specific purpose (i.e. connectivity for a LOB system). Fast forward to today and LANs are built to be pervasive, fast, secure, switched, multi-purpose and always available.

Similar to the evolution of LANs WLANs started small, were expensive and often to serve a specific purpose. As the WLAN continues to evolve organizations are starting to expect the same level of service that now exists on the physical wire.

Unfortunately many IS groups still have (or had during deployment) a narrow view of the WLAN. Part of it may be due to the security issues that existed, or the way it become pervasive in the Home or Hot-Spot markets first. Add to that the issues that come with using a medium which is inevitably shared and best-effort and you can really get yourself in trouble.

There are a lot of sites out there that already go into much greater technical depth than I’m looking to in something as simple as a blog post so I’ll only touch on the basics for those of you who are unfamiliar.

Wireless is inherently a shared medium, similar to a network where all the devices are connected to a hub rather than a switch (where every device gets a dedicated path). We could take the analogy even further back by comparing it to your Party Line versus switched phone circuits. Now when you have a small amount of traffic this works okay, however when you get a lot of devices on the network it can very quickly become an issue. Issues can be as simple as the network running slower, or they can be as agonizing as business applications ceasing to function.

With shared Ethernet (hub) you have collisions, and a means to detect and mitigate them, CSMA/CD. With wireless you have interference, and a means to avoid and mitigate, CSMA/CA. And yes even with the party line there is a way to try and work around the problems – “Hello, is anyone using this line?”

When the wireless network becomes critical to your business is when you really get into trouble. For example, when your doctor is using a VoIP wireless phone and doesn’t get a call. I’ve been there, believe me it’s not a fun situation to have the hospital director yelling at you about how worthless the network is.

So to make your life easier, keep your users from screaming, keep up with your SLA, save money, etc I challenge you to put even more effort into designing your WLAN than you did on your LAN. The devil really is in the details. If you don’t have experienced, competent folks on staff than hire a contractor to figure out the details and train your staff on what they need to know.

Cheers,
Erik Szewczyk

Category : Networking | Posted By : Erik | Comments [0] | Trackbacks [0]