Dot11 Guru

802.11, Design, random ramble, Troubleshooting, Wireless Profile

The secret step to passive validation surveys

There’s one step that I always perform when validating a wireless network. It’s something that typically isn’t considered the responsibility of the wireless engineer, but you will look like a superhero if you uncover it.

It doesn’t matter if I’m surveying an existing network, or validating one of my designs either, I always check it.

Always check the clients’ capabilities!

Here is a classic example, a passive survey was performed recently at a warehouse

Coverage is not great, there are definitely issues to be rectified

This isn’t a post about what can be done to rectify this design, there are some fundamental flaws which I will overlook. The point is that there is some type of coverage throughout the facility.

Post survey, I was performing my usual client capability checks, and I discovered this on the most common device in the facility

only UNII-1 and UNII-3 channels enabled

The only 5GHz channels that are enabled are UNII-1, and UNII-3. However, the wireless network is operating in UNII-1, and UNII-2. This means that the device will connect to 25% of the available access points. The wireless network for this device actually looks like this:

Without checking the client capabilities in this facility, this issue would have gone un noticed, and nothing we would have implemented would have fixed the issue.

Instead, we leave the site heroes.

Share this:

Leave a Reply