Understanding DHCP “Black Dots” and Connection Drop-offs

[peter86james]

We’ve been noticing recurring black dots in our DHCP logs, which seem to align with user reports of network drop-offs. Each time, the logs show “DHCP did not occur.” What’s puzzling is that these users are stationary no movement or device relocation yet it looks like a roaming event across access points (APs) occurs, followed by several minutes of network loss. We’re trying to understand what these black dots indicate in DHCP terms and whether they signal AP roaming, DHCP lease renewal issues, or something else causing these intermittent connectivity disruptions. Any insights would be appreciated.

[DeVoID]

I see 10.8r5 just dropped.. maybe that will fix the issue, but I suggest only do it on ONE AP, then grab your laptop, go there and see if you still get the black dots... also, be sure you dont have XIQ doing DHCP for you as well as your server.  I dont know if XIQ comes out the box set to DHCP... it might be something you have to manually disable in its interface.  Worth a check.

[sfolk]

I am having the same issue not sure when it started. The black dots coincide with unknown error messages in the "Client Monitor and Diagnosis" tool. Also there was a document on the Extreme community portal Monday Nov. 17th regarding this issue but it has since been removed. See screen shots attached.

[sfolk]

Forgot to say when you see a black dot with "DHCP did not occur" you will see this in the "Client monitor and diagnosis" 

[Elwin]

Those black dots usually mean the AP couldn’t complete a DHCP exchange. It happens when the client drops briefly during reauthentication or channel change. Check if DHCP lease timers are too short and watch for 802.1X reauth events that interrupt renewals.

The 10.8.4.0 firmware also had a bug causing this update to 10.8.4.1 or later.

Extreme Networks Troubleshooting DHCP Relay/Client Issues
How DHCP Works