Bruce Hubbert who writes the Freakquency blog has another good post titled, "The Myth of the Self-Monitoring WLAN." Duke University recently suffered a WLAN outage caused by an unanticipated flood of ARP (address resolution protocol) traffic. The details of the failure are used to demonstrate the need for network and WLAN monitoring that goes beyond conventional proprietary end-to-end solutions.

Hospital IT shops can be very keen on single vendor solutions - sometimes to the point of accepting significant shortcomings in parts of the vendors comprehensive offering. This tendency applies to networking in spades. Certainly you need central management, but you assume the AP and controller vendor has all the answers at your own risk - as Duke learned.

Certain vendors are taking this to extremes, offering hospitals WLAN site surveys and recommending the replacement of any technologies that don't sport their logo. Hospitals have received "advice" to replace $300,000 wireless patient monitoring systems because they weren't validated for that vendor's APs. The justification for these recommendations is that I just bought a new 30' sailboat third party systems can't be integrated into our enterprise solution. (If a vendor offers to do a free site survey of your facility, by all means take them up on it - just be sure to have someone else review the findings and offer a less biased assessment.) "And the story sounds so great, "Implement our solution and it will fix itself when it breaks and protect itself when security policies are breached." Who wouldn't want that?"

the truth is a little more complicated. As we have seen from previous
posts, sometimes the solution doesn't behave the way your business
practices need. Similarly, sometimes there are security problems within the infrastructure itself. So what to do?

In addition, as much as big market leaders would like to believe that single vendor
solutions are the new "best of breed," we live in a multi vendor world.

One should not blame the infrastructure for not getting this right at
the outset nor should one blame Mr. Miller. He was correctly reading
what the controllers were telling him. But it shows how important it is
to have a separate, 3rd party solution also available to get down to
the bits and bytes or even spectrum analysis (if the problem should be
something other than 802.11 protocol madness.)

Unlike commercial office space, or an open warehouse, the WLAN environment can be extremely challenging. Putting all your eggs in one network vendor is fine when all you're doing is supporting portable users moving from room to room charting or administering drugs. But when you start adding things like wireless VoIP, indoor positioning or wireless medical devices - with truly mobile users crossing subnets - look out.

Be sure to read Bruce's post, he's got some great recommendations.

UPDATE: Here are some previous posts on WLAN issues: Cisco Stumbles in Health Care, and Cisco Wireless LAN Technical Issues - Update.