Channel usage sometimes larger than 100%

[fuji246]

Sometimes i saw to channel usage larger than 100%, is that normal, any links point to how the channel usage is calculated?

And the bps looks smaller than expected, is that due to the 802.11 capturing in poor performance? The usage is around 100%, but the bps is near 1~ 2 mbps.

[br101]

Usage% now assumes a maximum bandwidth of 32Mbps. This should be improved/fixed by calculating the max bandwidth for info bars (Usage%) based on channel width. It's on my TODO.

Usage calculation is based on the time a packet spends on the channel. A 1500Byte 1MBps packet needs more time ("airtime") on the channel than a 54Mbps packet of the same size. So many many packets with 1-2 Mbps can easily bring your usage to 100%.

[fuji246]

Hi, is that fixed? I'm currently troubleshooting a wifi packet drop issue. Sometimes i saw very large loss, up to 10%-30% periodically, i checked the wifi performance(those metrics are getting from horst, but not the latest version)

Is the channel usage and retry ratio high to cause that large packet loss? Another question is because not all 802.11 packets can be captured, is the channel usage and retry ratio still valid?

Thanks!

[br101]

This issue is still open... So max bandwith is not calculated correctly and assumed 32Mbps, but this just makes the "Usage" sometimes more than 100% and does not affect the other values.

The issue you are seeing with retries may be (not sure): large packet loss causes retries to go up. Many retries can saturate the channel, so other stations are seeing high packet loss as well and then the retires get even higher...

Of course 'horst' can make it's calculations only from the packets it can capture...