Data Rates - best practices?

[rcoote5902_2]

Are there any best practices for 802.11a/n and 802.11b/g/n data rates as far as which to set as mandatory/supported etc?

I'm looking at optimizing our current deployment and have started by  disabling some of the lower data rates in the 2.4 range - everything  below 12 Mbps.

Current setup is as follows:

802.11b/g/n:
1 - Disabled
2 - Disabled
5.5 - Disabled
6 - Disabled
9 - Disabled
11 - Disabled
12 - Supported
18 - Supported
24 - Mandatory
36 - Supported
48 - Supported
54 - Supported

802.11a/n:
6 - Mandatory
9 - Supported
12 - Mandatory
18 - Supported
24 - Mandatory
36 - Supported
48 - Supported
54 - Supported

I'm not worried about b clients - we don't have any - and even if we did I don't want them on the network.

[pcroak]

Hi There,

You're on the right track, here are a few additional guidelines:

1. Determine your coverage levels along with the desired minimum data rate required by your application(s). Disabling lower data rates does have a significant impact to your coverage area.

2. You have already prevented 802.11b clients by disabling  1,2,5.5,11 -- so that piece is taken care of.

3. Typically, we see deployments having the lowest enabled data rate set to mandatory. This allows for the best client compatibility. You can also have higher mandatory rates, but then you need to confirm that all client devices will in fact support those higher rates. (Most clients do, but there are some exceptions). Worth noting here is that multicast traffic will be sent out at the highest mandatory data rate -- so if you have the need for higher bandwidth multicast traffic, you may want to have another data rate(s) set as mandatory.

-Patrick Croak

Wireless TAC

[rcoote5902_2]

Thanks Patrick,

Is there a reason why the default settings on the controller have 6, 12, and 24 set as mandatory for 5.0 Ghz?

Rob

[pcroak]

Hi Rob,

I'm not really sure why we have those values as the defaults. It doesn't hurt to have multiple mandatory rates, as long as the clients in the environment are compatible with all of them. I can only assume that those values were determined to be a good "middle ground" setting for deployments.

-Pat

[George Stefanick]

Normally, you will see (2) mandatory rates set. Rules of tumb:

Lowest is managment frames

Hightest is multicast frames

If you keep these "2" in mind you can never go wrong ... Picking the right rate is a different challenge.

Everything else is just "extra" and not needed.

[secsecsec]

Hello,

The IEEE required only mandatory support of data rates of 6, 12, 24 Mbps, the reason behind this because each of these rates using a different modulation ( BPSK,QPSK and QAM).

Some (very few) 5G capable client drivers were written to accept only required the support of 6, 12, and 24M rates (“Basic Rates”) – or they wouldn’t connect.

Further still, there are a few 5G capable client drivers out there that will only accept 6, 12, or 24M, but nothing else.

[Leo Laohoo]

I'd normally disable the 802.11b data rates (1, 2 ,5.5 and 11) disabled and leave the rest enabled.

[George Stefanick]

What is really key, first before shutting off the data rates is: Does your wifi design support the ability for you to disable the lower data rates. If it does, then have at it!

When I speak to IT folks about network utlization and share with them the DATA selection. I ALWAYS tell them, DONT go back and just shut off your 1,2 and 5.5 if you dont know if your wifi design supports it.

Other wise. Clients at the edges that are connecting at 1 and 2 are working fine. You shut that off, they will have NO coverage.

just my 2 pennys

[pcroak]

+5

Great advice George -- while we all may want to disable 802.11b, if the given design could create coverage holes this will have a negative impact.

[rcoote5902_2]

Thanks for the replies - points all around.

I spent the better part of 6 months monitoring our existing clients and had only 2 b devices (old Cisco 7920 wireless phones) which I have since decommissioned.  So, I'm fairly comfortable eliminating those rates completely.

I'll leave the data rates as above for now and see if any issues arise when staff and students start filtering back into the schools.

Cheers,

Rob

[Alex Pfeil]

Is there a way to see if any devices are connected at 1Mbps, etc?

Thanks,

Alex

[jmecklenburg]

There's a any way to see which device are connected in the Low Data Rates?

I have a few sensor connected at 802.11b and I want to know if this sensor will be impact if I disable low data rates.

Thanks

[Scott Fella]

You can use tools like WiFi Explorer or tools like the Aircheck G2 which shows clients and their advertised capabilities which includes data rates. Older devices typically need the low rates. The best way is to change it and see if the devices drop off.