If you follow a bunch of CWNP-associated Wi-Fi professionals on Twitter you would be familiar with the frequent, casual analysis of hotel Wi-Fi. Maybe you like to do a little bit of looking beyond the SSID when you're away from home? The shared findings help remind us all what to avoid when we setup Wi-Fi.
Screenshots from inSSIDer (by Metageek) were commonly featured in these tweets to help visualise the frequency - especially when channel use was less than good.
Historically the common culprit would be poor planning of the 2.4 GHz frequency space. I've seen examples of hotels using contiguous channels 1 through 11 (including the overlappers 2, 3... 8 etc.). It's common to have wide 40 MHz configuration - which is a terrible idea in 2.4 GHz anywhere there is more than a single radio (in a desert with a population of one).
We see bad setups in the 5 GHz channels as well. Channel re-use is over-represented - sometimes hotel radios have no channel planning whatsoever. Having every access point using the same channel in 2.4 or 5 GHz is a bad idea. Contention for air-time can lead to a performance downgrade if too many people are using the Wi-Fi at the same time on the same frequency. It may cope to a certain amount but if the contention domain extends across a highly populated hotel it's likely to be bad.
But outside of simple channel design issues there are other things that are worth investigating if you want to be thorough.
Keith Parsons found an example of a hotel where he was able to connect to a Wi-Fi network with good 802.11 metrics - high MCS rate, 2 spatial streams and an outstanding signal to noise ratio - yet speed tests were terrible. Something beyond the Wi-Fi shaped his connection to 350 Kbps (possibly the Internet back-haul). The Internet bandwidth must be sufficient on any network to cater to the users requirements. Having a shiny Wi-Fi 5 or 6 (802.11ac or 802.11ax) capable infrastructure won't help anyone if the pipe out is smaller than a soda straw.
If you're familiar with 802.11 protocol analysis you might try capturing Wi-Fi frames in a tool like Wireshark or Omnipeek. With the right filters you can visualise relative re-transmission rates on a channel in your location. When you study for Certified Wireless Analysis Professional you learn about many of the Information Elements in the 802.11 standard. Information Elements (IEs) hold key information about the capabilities or configuration of a particular BSSID. Sometimes it's a bit too much to get right into the weeds of wireless frame capture and analysis. But there is another way to inspect the IEs if you have an Apple Mac.
Wi-Fi Explorer is a brilliant application brought to us by Adrian Granados. In the simple view it lists the nearby Wi-Fi networks that your Mac can detect. Within the Advanced Details tab the IEs are brought to you in a expandable tree of wonder. In my screenshot example above I have expanded the QBSS Load details of the BSSID to which I was associated. I am able to see there are currently 2 stations (including myself) connected. The Access Point even provides details about the channel utilisation which is useful if high contention is suspected.
By looking at the IEs with Wi-Fi Explorer you could check what data-rates a BSSID was configured to support. I remember seeing a tweet where someone detected the hotel was rate-shaping clients by restricting association data-rates to 1 and 2 Mbps. This would most certainly result in counter-productive results as this is not the intended use of data-rate configuration. Low data-rates equal poor performance for modern Internet access.
I definitely recommend Wi-Fi Explorer (I have the Pro version) as a day to day Wi-Fi professional tool - there is a lot more to it than mentioned here.
Fast, Free and Frictionless... (@KeithRParsons)
Here is a blog post about the Rules for Successful Hotel Wi-Fi from Keith Parsons. He wrote it way back in 2014 but it still holds true today!
As demonstrated it is not just about good channel design. There is more to inspect and always plenty to learn from each other.
If you have any stories to share about bad hotel Wi-Fi please comment, and keep sharing your findings on Twitter.
Written by Matt Sutherland
We build and optimise networks. Continuous learning is our secret to being good. Along the learning journey we will share things here...