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Any DHCP issues with disabling low data rates?

Hi All,

 

I recently was able to retire the last 802.11b device in my household (an old Fitbit Aria). I hadn't had Legacy mode enabled in ages, but it still worked (I don't know why). Since then, I've gone in and checked "Disable CCK Rates" (and "Also require clients to use rates at or above the specified value") for my SSIDs, and set the minimum data rate to 6Mbps. 

 

However, and I'm not positive this is the case, it could just be Dashboard being weird, one device (a Sense power meter) randomly shows a 169.254 address, then flips back to it's normal address. And I'm worried setting this upper minimum rate might be preventing DHCP from working right/reliably on this device. 

 

Anyone seen issues like this? Am I crazy? 

 

Thanks! 

USG, UniFi AP AC Pro, UniFi US-16-150W, Unifi US-8, UCK-G2-Plus, UVC-G3, UVC-G3-Flex

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Established Member
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Re: Any DHCP issues with disabling low data rates?

If you don't have any "b" clients in the cell, then adjusting minimum bitrate will increase cell efficiency. What you actually do, behind the scenes, is disallowing lower MCS values. This change should go in conjunction with AP TX power level just to minimise unnecessary signal to be transmitted outside the cell where low MCS no longer accepted (this will also reduce creating reflection and noise). Once the basic data rates agreed during the association, they should be respected by the clients and AP during whole association period. Remember the actual data rates (when the client transmits data) can be much higher than basic rates. Anyway, this is just FYI only, DHCP issue is a separate issue and should not be related to the minimum bitrate setting.

Thanks,
Myky
CWNA
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.

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Re: Any DHCP issues with disabling low data rates?

@staze
There was a controller (or was it firmware?) version a few weeks ago, which showed IPs strangely (but it was just cosmetic) - which version are you using?
But then the 4.0.10 firmware has been getting a lot of reports about IoT devices disconnecting - most people have downgraded to 3.9.54
The 11b and minimum rates shouldn't mess with DHCP - either the client will be able to connect or it won't.
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Re: Any DHCP issues with disabling low data rates?

Hello @staze,

 

What firmware version are you on?

Are you only seeing this in the client list or also on the client itself?

 

 

Regards,

Glenn R.

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Re: Any DHCP issues with disabling low data rates?

Firmware for AC-Pro is 4.0.15. Controller is 5.9.32. 

 

I can't tell on the client as it's an IoT device. It does occasionally act like it's got connectivity issues though.

 

My wonder is if it's trying DHCP using some low bitrate =/

USG, UniFi AP AC Pro, UniFi US-16-150W, Unifi US-8, UCK-G2-Plus, UVC-G3, UVC-G3-Flex
Established Member
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Re: Any DHCP issues with disabling low data rates?

The client will never use anything below a basic (mandatory) rate and these rates are agreed between the client and AP during the association process.

The full process described in the KB below:
http://www.revolutionwifi.net/revolutionwifi/2012/12/wi-fi-probing-behavior-and-configured.html
Thanks,
Myky
CWNA
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
Regular Member
Posts: 480
Registered: ‎12-17-2015
Kudos: 183
Solutions: 8

Re: Any DHCP issues with disabling low data rates?

awesome. =)

I've asked the vendor to see if there are any logs backing up if the device is really losing connection. As far as data rates, I'm seeing a lot of conflicting info online about whether you should bother turning off lower data rates. The device doesn't have a weak signal, but I suppose interference could occasionally hammer SNR and comm could fail without that lower data rate... or does the client cache that lowest agreed data rate?
USG, UniFi AP AC Pro, UniFi US-16-150W, Unifi US-8, UCK-G2-Plus, UVC-G3, UVC-G3-Flex
Regular Member
Posts: 480
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Re: Any DHCP issues with disabling low data rates?

As a quick note, this is a home setup with a single AP.
USG, UniFi AP AC Pro, UniFi US-16-150W, Unifi US-8, UCK-G2-Plus, UVC-G3, UVC-G3-Flex
Established Member
Posts: 2,226
Registered: ‎04-21-2015
Kudos: 305
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Re: Any DHCP issues with disabling low data rates?

If you don't have any "b" clients in the cell, then adjusting minimum bitrate will increase cell efficiency. What you actually do, behind the scenes, is disallowing lower MCS values. This change should go in conjunction with AP TX power level just to minimise unnecessary signal to be transmitted outside the cell where low MCS no longer accepted (this will also reduce creating reflection and noise). Once the basic data rates agreed during the association, they should be respected by the clients and AP during whole association period. Remember the actual data rates (when the client transmits data) can be much higher than basic rates. Anyway, this is just FYI only, DHCP issue is a separate issue and should not be related to the minimum bitrate setting.

Thanks,
Myky
CWNA
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
Regular Member
Posts: 480
Registered: ‎12-17-2015
Kudos: 183
Solutions: 8

Re: Any DHCP issues with disabling low data rates?

makes sense. and yeah, just had someone explain minimum and mandatory (in Cisco parlance), and that then explains what the "Also require clients to use rates at or above the specified value" setting does.

Yup, weird. I'll wait to hear from vendor if there's any way to see if the client is actually losing contact, or if it's something else. Could just be html caching in controller too (showing 169.254.x.x. but then it refreshing to be a valid IP).
USG, UniFi AP AC Pro, UniFi US-16-150W, Unifi US-8, UCK-G2-Plus, UVC-G3, UVC-G3-Flex
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