Why You Should Disable Lower Legacy Data Rates

[thiggins]

A little on the technical side, but worth a read. Also talks about sticky clients.
http://divdyn.com/disable-lower-legacy-data-rates/

Good argument for using APs vs. converted consumer routers. Most don't allow controlling supported data rates.

If you want to at least disable B rates, look for settings for 1,2,5.5 and 11 Mbps data rates. This Cisco article has a good screenshot of one of their controllers that makes it easy.

 

[coxhaus]

I use Cisco WAPs and they have on their forum how to do this for my Cisco WAP321 units. I did this over a year ago. You pull out all the low connection rates.

PS
I think this is how I evolved to only running 5GHz. I dropped 2.4GHz altogether. It seemed simpler than managing slow connection rates.

 

[Shabbir Rao]

Thumbs Up

 

[Ronv42]

I miss some of the great configuration settings of Cisco hardware but again you have to know what you are doing when you get into this type of detailed configuration.

 

[sfx2000]

If you want to at least disable B rates, look for settings for 1,2,5.5 and 11 Mbps data rates. This Cisco article has a good screenshot of one of their controllers that makes it easy.

Basic Rates - one cannot disable the basic rates, which are 1, 2, 5.5, and 11 - this is mandatory per 802.11 in the ISM 2.4GHz band... many reasons for this, but much has to do with modulation and how receivers self-calibrate (open loop) to determine appropriate Tx power - this is why Beacon's in 2.4GHz are always transmitted at the 1Mbps rate...

Supported Rates - this is a different story, and this is where the guidance for high-density deployments rings true, in that 18Mbps is probably the minimum for an 802.11 client to attach - and the setting for enterprise level AP's can allow for this... 18Mbps is important, as most silicon supports this in their supported rate set epigrams on the beacon - some offer different rates as well, and enterprise AP's can manage that list to some extent, and then offer additional supported rates in the Extended Support epigram - but the Supported Rate epigram dates back to 802.11b, as part of the legacy support mandate that IEEE is held to...

HT/VHT have different mechanisms - but keep in mind that Basic Rates will always be there...

Attached - Did a quick scan, and was able to catch most of the major silicon vendors - so you can review and make decisions..

 

[sfx2000]

And following up - 11b/g/n clients send their supported rates as part of the 802.11 Probe Request, so the AP can make some decisions before allowing a client to connect - e.g. if the client doesn't support 18Mbps, then don't associate - still have to send a Probe Response to stop the client from continuing to Probe, but the AP is not required to complete the association.

The big thing - don't want 11b clients on the network at all - as they will force 11g/11n AP's into ERP Protection, and this hurts all clients associated within that Basic Service Set. One also doesn't want low data rate 11g/11n clients in the BSS, as they will suck up all the airtime (Airtime fairness helps out a bit here, but still...).

 

[sfx2000]

For many consumer grade AP's - while you might not have all the flexibility of an enterprise/carrier grade AP, one thing you can do is put the AP into 11g/11n mode (if allowed by the UI), and many AC1900 class AP's have a multicast rate, which if you set it to 11Mbit or above, can keep slow clients from sucking up airtime...

That setting, in a small multiple AP environment, typical of the SNB forum crowd, can also help with "sticky" clients, as the AP can use that rate to force a disassociate to the client, and put the client back into AP search mode for a better AP.

YMMV - as tweaking these rates can lead to usability issues if trying to cover a large footprint with a few possible AP's - we're all frugal at the end of the day, and I know, speaking for myself, that I try to get by with as little as possible...

 

[stevech]

Using 11g or even 11b rates.. some use cases with lower data rate needs trade using that low rate for much longer range. Because the lower rates tolerate a weak signal better (low SINR tolerated).

Example: infrequent telemetry in machine to machine (M2M) applications.

 

[thiggins]

SFX: How about writing up a short How To article using an actual example or two?

 

[sfx2000]

SFX: How about writing up a short How To article using an actual example or two?

I'm thinking perhaps not, as it's a loaded gun, and for many, it might harm than help and lead to the usability issues I mentioned above...

In a high density layout (many clients/many AP's) this makes sense, but this is a bit out of scope for SNB for the gear than most folks have at hand, and I don't think most would want to invest a couple of thousand dollars (US) to make the most of it.

 

[sfx2000]

alt-argument - I see his point - all depends on the network plan...

http://www.sniffwifi.com/2016/01/why-you-shouldnt-disable-low-wi-fi.html