hostapd on USB WiFi capped at 5mbps

Lockheed · 2016-07-13 13:36:15

I have a server/router with three WiFi interfaces:
1. PCIe atheros
2. Realtec Nano receiver (tiny small thing with RTL8188CUS)
3. USB AR9271 (TP-Link 722N)

I test the WiFi speeds from a client 30 cm from the antennas.

On hostapd AP run on card 1, I get 60/60Mbps on speedtest.net
On hostapd AP run on card 2, I get 2/2Mbps on speedtest.net
On hostapd AP run on card 3, I get 5/5Mbps on speedtest.net

I though 2 is bad because of its tiny size, so I got a universally recommended card 3, but the modest increase in disappointing. On RPi forums I read that people get even 40/40 on 2, so I start to think that this my results are not how it should be.

I doubt this is related to USB bus overload because it is the same in every USB socket I have (3 different buses), including a USB 3.0 one.

Here is my hostapd.conf for reference:

interface=wlp0s16f0u2
bridge=br0
ssid=(-: some wifi :-)
channel=1
ieee80211n=1
wmm_enabled=1
wpa=2
wpa_passphrase=supersecret
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
auth_algs=1
macaddr_acl=0

The ieee80211n=1 + wmm_enabled=1 part is only on 3 (TP link), otherwise the configs are the same for 2 and 3.

If my misgivings are correct and those speeds are less than what expected, what could be the problem?

Last edited by Lockheed (2016-07-25 08:18:01)

JohnBobSmith · 2016-07-13 16:38:57

I wonder if you are actually *too* close to the router currently. Perhaps I'm wrong, but I believe that the bands will overlap if you're too close, thereby degrading performance. You could try running all the tests again just a lit bit further away. Say, 1 meter? That would rule proximity out. The next thing to try is ensuring that your channel=1 line matches the channel being broadcast from the router. Finally, see if you can try changing that channel to the highest possible value. This is 11 for me in north america. Perhaps there is some interference or otherwise on channel 1.

Good luck!

Lockheed · 2016-07-13 17:38:43

JohnBobSmith wrote:

I wonder if you are actually *too* close to the router currently. Perhaps I'm wrong, but I believe that the bands will overlap if you're too close, thereby degrading performance. You could try running all the tests again just a lit bit further away. Say, 1 meter? That would rule proximity out.

Well, I went so close to the source because I was getting exactly the same results from another room. So the proximity issue is ruled out.

JohnBobSmith wrote:

The next thing to try is ensuring that your channel=1 line matches the channel being broadcast from the router. Finally, see if you can try changing that channel to the highest possible value. This is 11 for me in north america. Perhaps there is some interference or otherwise on channel 1.

I also tried channel 6. Those are the cleanest around. I just tried 11, too. The best I am getting from TP link card is 5/7Mbps.
It is worth to note that hostapd running on PCIe has no problem reaching 60/60 on the same channels.
Also, interestingly, the signal strenght from card 2 is higher than from card 1.

Last edited by Lockheed (2016-07-13 17:41:59)

JohnBobSmith · 2016-07-13 19:26:53

Is it possible you have bad usb devices?? Ones that are not supported or require odd drivers to work? USB 3.0 devices in a 2.0 slot?? I my rather shitty experience with wifi, I could never get a good connection, when compared to my pci-e device (which in turn had issues...). Could it be possible that your router is throttling the USB adapters? Is something like QoS running? Sorry for the many questions and no answers yet but I hope with the right information maybe the issue will present itself in a clearer way.

Lockheed · 2016-07-13 19:52:40

Thank you for your interest!

No, the devices are fine. Inserted to other machines and connected as clients, they reach decent speeds. They are both USB 2.0, too. There is no throttling. It's a simple hostapd setup, bridged to br0, and connected to a pfSense in a VM.

JohnBobSmith · 2016-07-14 02:12:47

Well the first thing to check then, especially since: 1) I suspect a software problem and 2) all of my other ideas have been ruled out is to look at the drivers and hardware. It's important to be precise here because, in my experience, vendor/driver/hardware ID's can be quite confusing. Can you please post the output of lshw -C network here? If your USB devices aren't listed, try a repeat with -C bus instead. If outputs are large, please use a pastebin service. This will tell us the hardware. Now for the drivers. Go ahead and run lsmod with no arguments and post that here as well. That should give us enough information to begin ruling out bad drivers or poorly supported devices.

EDIT: You're very welcome. Good questions deserve good answers.

Last edited by JohnBobSmith (2016-07-14 02:13:40)

Lockheed · 2016-07-14 07:00:47

Here we go:
http://pastebin.com/raw/9XULtrxm
http://pastebin.com/raw/ce338HpM

JohnBobSmith · 2016-07-14 16:42:50

Any or all of the following:

rtl8xxxu               90112  0
rtl8192cu              69632  0
rtl_usb                20480  1 rtl8192cu
rtl8192c_common        45056  1 rtl8192cu
rtlwifi                65536  3 rtl_usb,rtl8192c_common,rtl8192cu

May have something to do with it. Unfortunately I still couldnt find your USB driver/device names. Can you please paste back the output of lsusb? Hopefully than we can start making connections to any bad drivers/devices.

Lockheed · 2016-07-14 16:49:31

The modules you listed are for the 2nd card (Realtec Nano). But it is unplugged and we are considering TP link card which is Atheros-based:

Bus 003 Device 002: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n

Lockheed · 2016-07-25 08:17:28

I enabled UHCI and XHCI hand-off in BIOS, which was previously disabled. I hoped it would help, but it didn't. WiFi speeds of USB dongle APs are still capped at 5Mbps.

Arch Linux

#1 2016-07-13 13:36:15

hostapd on USB WiFi capped at 5mbps

#2 2016-07-13 16:38:57

Re: hostapd on USB WiFi capped at 5mbps

#3 2016-07-13 17:38:43

Re: hostapd on USB WiFi capped at 5mbps

#4 2016-07-13 19:26:53

Re: hostapd on USB WiFi capped at 5mbps

#5 2016-07-13 19:52:40

Re: hostapd on USB WiFi capped at 5mbps

#6 2016-07-14 02:12:47

Re: hostapd on USB WiFi capped at 5mbps

#7 2016-07-14 07:00:47

Re: hostapd on USB WiFi capped at 5mbps

#8 2016-07-14 16:42:50

Re: hostapd on USB WiFi capped at 5mbps

#9 2016-07-14 16:49:31

Re: hostapd on USB WiFi capped at 5mbps

#10 2016-07-25 08:17:28

Re: hostapd on USB WiFi capped at 5mbps

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