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Patching coverage holes

Jun 16, 20032 mins
Cellular NetworksNetwork Security

Q. I’m experiencing periodic coverage holes in my wireless network.  How can I prevent this?

I’m experiencing periodic coverage holes in my wireless network.  How can I prevent this?

This can definitely be frustrating, and a difficult problem to solve if you can’t reproduce the situation. Many factors could be causing the problem, including: signal attenuation on your radios, interference from external devices (such as a Bluetooth client, etc.), changes in physical topology (someone moving a filing cabinet), etc. The list goes on and on.

To make matters worse, coverage holes can lead to security threats. In a network that has some method of detecting rogue access points, not having proper coverage in a given area impacts the system’s ability to detect these security threats. Also, the coverage hole may be intentional – created by a malicious person.

The occasional problem you describe is very complex to resolve, because with traditional 802.11 network devices, it requires that you catch the problem when it occurs. This requires using site survey tools, and some staff on-site to identify the problem when it occurs. Warning: This can be costly.

We’ve also noticed that many people have a tendency to add additional capacity in problematic areas, but in many cases this could cause more harm than good. Adding additional access points in an area without proper planning can create additional interference with the existing network, and may even create a new set of problems (such as poor performance).

Using new wireless LAN systems that provide intelligent RF management may be able to help. Some products can detect, report and fix coverage hole problems such as the one you are experiencing. Some can also monitor the health of the RF network, and optimize coverage to ensure maximum performance under load. The systems can also reconfigure the network to eliminate potential interference when new access points are deployed.