Poor wifi performance


#1

Hi,

I’m experiencing very slow wifi speeds.

When I test with iperf, I get these results:

root@turris:~# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.0.1 port 5001 connected with 192.168.0.230 port 52612
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec  1.07 GBytes   921 Mbits/sec
[  4] local 192.168.0.1 port 5001 connected with 192.168.0.138 port 54326
[  4]  0.0-10.0 sec  14.6 MBytes  12.2 Mbits/sec
[  4] local 192.168.0.1 port 5001 connected with 192.168.0.138 port 54334
[  4]  0.0-10.1 sec  18.4 MBytes  15.3 Mbits/sec

This are 3 connections from the same client laptop connected via respectively wired, wifi 2.4GHz and wifi 5GHz.

As you can see, performance over the wired connection is fine, but the wifi is very slow. The 5GHz is a little bit faster than 2.4GHz, but not much. If I move physically closer to the router, then the performance improves, but only up to about 20-30 Mbits/sec, which is still very bad.

What could be the problem?

Jef


#2

That is expected. But how close to the router did you move?

There can be a number of reasons for less than perfect wifi performance, e.g. channel congestion in areas densely populuted with access points. There are tools for ios/android (eg. Net Analyzer) to assist in accessing the wifi landscape (signal strength, channel utilization etc) and those are usually a good starting point.


#3

I tried moving right next to the router, about 0.5 to 1m distance.

I already checked with a wifi analyzer. The 2.4GHz is indeed very crowded. There are several other access points on channel 1, 6 and 11. But on 5GHz there are no other access points at all.


#4

Indeed then you should get some decent bandwidth at least on the 5GHz band at such a distance.
Whats is the reading of the router’s signal strenght on the 5GHz?
Unfortunatelty I would not know of how to troubleshoot this any further. :disappointed:


#5

This is why there is 5 GHz. I have the same. A gazillion 2.4 GHz AP’s and SSID’s and hardly any 5 GHz.
Guess where I have good performance. If necessary buy a few mox’s for extra AP’s for other rooms.


#6

In the luci webinterface, the signal strength fluctuates between 65 and 70%:

5.0GHz: 70% Signal: -61dBm / Noise: -104 dBm
2.4GHz: 70% Signal: -62dBm / Noise: -95 dBm

What’s the throughput that I should be able to achieve with my Turris Omnia? The maximum speed of 1.3 Gbps (5 GHz) and 450 Mbps (2.4 GHz) is probably way too optimistic, but what kind of speed can you expect in practice?


#7

With 0.5 m distance on a direct line of sight between router and client the signal strength should probably be around -40 dBm (on either band) but definitely not less than -50 dBm (i.e. -50 to -100) and probably 1 -1.1 Gbps on the 5 GHz and 400 Mbps on the 2.4 GHz, a bit depending also on the channel encryption and management frames.

Other area of of your wifi landscape then depending again on the layout of the area (like wall, angles etc), channel saturation, client capabiities, firewall inspection…

There are also options in (L)uCI to adjust Transmit Power and Distance Optimization, as well as Country Code. Latter could have an impact on the transmitting channel and transmitted power as well, according to country regulations.

One other impact factor is the frequency of the chossen band, e.g. 20/40/60/80/160 MHz.


#8

Not all wifi client devices are supporting 5GHz and/or are placed in spots within the wifi landscape that are hard to reach and thus 2.4GHz is needed


#9

For the first, buy a new device for the second buy a mox to use as ap.


#10

Some wifi client devices are designed by purpose for only 2.4GHz use, particularly IoT devices, and there is not much of a choice then. Some users might not be in the position to afford additional (lan/power line to) wifi extenders and just have to make the best out of one device and the given environment, albeit of course extending the wifi may improve wifi performance in certain areas.


#11

There is also Lora, https://lora-alliance.org/
But to move back ontopic, I’ve given up on 2.4GHz. It’s nearly unusable in dense city housing.
Given the OP his own research using 5 GHz is the obvious recommendation.


#12

ineed -60dbm while “near” router means something hardware is faulty.
maybe check cables inside router (guide in forum)


#13

I’ll have a look at the hardware tonight. Anything particular to check?


#14

perhaps worth checking Slow WiFi and bad signal finally solved


#15

I’m not sure whether that is the problem, because I’m seeing low speeds on both 2.4GHz and 5GHz. But I’ll check anyway.

Note that I don’t have an mSata disk or a USB3 device attached. The wifi cards should be at their default location, because I didn’t change them. On the 2.4GHz wifi card I have configured two SSID’s (normal and guest network), but I don’t think the guest network is the problem, because it was already slow before. (Before adding the guest network I used another router to provide the guest network, but that one died a while ago.) On the dual wifi card, I have configured only one SSID on 5GHz.

BTW, I’m not sure if this is related, but very often when I try to change any of the wireless settings in luci, the wireless radio gets disabled, and I need to reboot my Turris Omnia to get it working again.


#17

Then it is unlikely to be the cause.

that is expected behaviour as the wifi gets a restart and it takes a moment for the cards’ reboot.

that should not be necessarry


One other issue could be, at least on the 2.4GHz band, interference from bluetooth devices.


#19

or babyphones or walkietalkie or microwave oven …
2.4ghz is fair game for everthing

but again, as there was an issue with loose antenna cables/screwings, i suggest u check this first.


#20

I checked the cables, and everything looked fine. But afterwards my wifi speeds have improved. I now get around 50Mbps on 2.4GHz and 250Mbps on 5GHz with iperf. That’s at a distance less than 1 meter away from the router. That’s already a nice improvement, but still not really great either. Hmm, what else could be the problem.


#21

How long does that normally takes? A few seconds or several minutes? Is there a way to check what is going on? I tested yesterday and after 5 minutes the 5GHz card was still not up. But after a reboot it came up again.


#22

Say perhaps in the range of 30 - 60 s.

Yes, there are probably pointers in the syslog (LuCI -> Status -> Sytem Log)

That sounds something is wrong, maybe something similar being dicusssed here Omnia 3.10 disappeared Wi-Fi