Optimizing 1142 Throughput

[brian.emil.harris]

I'm using an AIR-AP-1142N-A-K9 in a home environment, and trying to optimize throughput.

Internet connectivity is an "up to 600mbps" cable Internet service from Comcast, using their Technicolor CGM4140COM "xFi Gateway", in bridge mode, connected to a Ubiquiti ER-4.

The ER-4 is connected to a WS-C2960CG-8PC-S.

Primary workstation is physically connected to this switch.

Speedtest.net returns result of 593.88mbps down, 18.02mbps up

AIR-AP-1142N-A-K9 is connected through a AIR-PWRINJ4 to the same switch.

Testing on an iPhone 11 Pro Max yields downstream most recently of 81.6mbps down, 17.9mbps up, with free air/visibility to the WAP, at a distance of approximately 15-20 feet.

Port configurations are identical on the switch.

Looking for suggestions on tuning the WAP better.

On another note:

show dot11 associations <MAC> for the iPhone provides this data:

Current Rate : m15-4 Capability : WMM 11h
Supported Rates : 6.0 9.0 12.0 18.0 24.0 36.0 48.0 54.0 m0-2 m1-2 m2-2 m3-2 m4-2 m5-2 m6-2 m7-2 m8-2 m9-2 m10-2 m11-2 m12-2 m13-2 m14-2 m15-2
Voice Rates : disabled Bandwidth : 40 MHz

So, the iPhone is at a rate of m15-4, but the WAP only supports m15-2 - is the 4/2 the number of spatial streams, i.e. the WAP only supports two spatial streams, but the iPhone could support 4, if the WAP did?

m15 rates, 2 spatial streams and a 40mhz channel width would seem to allow 270mbps on a long guard interval, or 300mbps on a short guard interval (not really sure how/where to set guard interval), or 130/144 on a 20mhz width.

Either way, I seem to be falling fairly short of the throughput I should be seeing.

Any assistance you can provide would be most appreciated!

[Leo Laohoo]

Disable 2.4 Ghz if there are no clients using this.
Disable Data Rates from 1- to 11 Mbps. Make 12-, 24- and 48 Mbps Mandatory and the rest are Supported.

[brian.emil.harris]

2.4ghz is, sadly, used (Ring Cam doesn't do 5ghz), but it's a different SSID name.

For the 5ghz radio, the GUI shows that I can require, enable or disable, the following data rates:

6, 9, 12, 18, 24, 36, 48 and 54.

All are currently set to require.  So, I should disable 6 and 9, and leave the rest as require, but change 54 to enable?

MCS rates 0-15 are all set to enable, the only other option is disable.

[Scott Fella]

Try this: disable: 6, 9, 12 enable: 18, 36, 48 required: 24, 54.

[Scott Fella]

To add to Leo's comments, you also need to understand how you are performing the throughput test. Use iperf to test locally and not over the wan. Also keep in mind that wireless is half duplex, so with 40mhz, you can theoretically achieve half of what the client shows as the speed. If you see connection rate of 144mbps, then the theoretical max is half of that and less with more clients. Test using iperf, and follow what Leo suggested and see what you get. When you test with iperf, use the following flags: iperf3 -c -f m -b 2g -t 60 -u

[brian.emil.harris]

Thank you for the input/help.

I'll try dinking around with iPerf at another time - I do realize the half-duplex nature, I just figured with all things being equal, and using the same SpeedTest.net server, I should see better throughput on my iPhone via the 1142.

[Scott Fella]

Well using Iperf tells you what your throughput is without egressing over the internet. It will also tell you what your throughput really is. 1142 is only 802.11n capable so don’t expect anything above 60-80Mbps

[patoberli]

To get the maximum speed, set the guard interval to short and enable 40 MHz channel width on 5 GHz. That should then show a client connection rate of 300 Mbps. This again will translate in real world ~135 Mbps maximum throughput, as long as there aren't many other clients using the same 5 GHz channels. More is not possible with this AP and 802.11n technology (the 3502 supports 450 Mbps, but in real world you barely reach 200 Mbps throughput).