Dramatically low speed of 802.11n AP mode on R52Hn

RouterOS Wireless Networking
1

Hello!

Prehistory: some years ago I have tried to use Mikrotik rb951ui-2hnd as my home router with WiFi. I have a laptop with Intel wifi adapter and couple other n-devices like to iPad. But the performance of WiFi was slow dramatically, n-mode was slowly than g-mode. I spend a lot of time to read Internet topics about this issue but nothing to help… So, my conclusion was that Mikrotik is a good router but wifi of it unfortunately is worth. I have turned off WiFi mode in Mikrotik, connected my Asus RT-N16 as Access point and in the same conditions got full speeds of 802.11n on 2GHz. It was RouterOS 5.xx times.

Now: For some reasons I’d like to build WiFi router based on Mikrotik again :slight_smile: Now we have 2017 year, RouterOS 6.40.5 and all 802.11n issues again :slight_smile: I have RB435 + R52Hn + two 4 dBi antennas connected by MMCX-SMA pigtail. Speed of n-mode is toooo slow, more slow as compared with my Asus RT-N16. The situation is the same as couple years ago. Maybe somebody could help to resolve this issue?

Here is my wireless configuration:

/interface wireless
set [ find default-name=wlan1 ] adaptive-noise-immunity=ap-and-client-mode ampdu-priorities=0,1,2,3,4,5,6,7 antenna-gain=3 \
    band=2ghz-g/n bridge-mode=disabled country=russia disabled=no distance=indoors frequency=auto frequency-mode=\
    regulatory-domain mode=ap-bridge multicast-helper=full rx-chains=0,1 ssid=Ivanov2 tx-chains=0,1 wireless-protocol=802.11 \
    wps-mode=disabled

My speed tests are very simple: I’m trying to download something big file from my NAS SMB share to laptop via WiFi. The results:

  • Laptop and Asus RT-N16, 802.11n mode, 130 MBps connection - download speed is over 5-7 MB/s (Megabytes per second).
    Laptop and Ruckus R500, 802.11n mode 2GHz, 300 MBps connection - download speed if over 10 MB/s (Wow!).
    Laptop and Mikrotik RB435 + R52Hn, 802.11g mode, 54 MBps connection - download speed is over 2 MB/s and stable (this is normal for g-mode).
    Laptop and Mikrotik RB435 + R52Hn, 802.11n mode, 130 MBps connection - download speed is lower then 1 MB/s and not stable (!!!).

The main question: Whats happens?

2

I would also wonder why …

3

This is how Mikrotik works with some devices. Normis confirmed it: http://forum.mikrotik.com/t/xiaomi-phone-low-wifi-tx-rate/93622/1
Probably they will not fix it soon (it is low priority). You shouldn’t buy Mikrotik as AP for non-Mikrotik devices. Actually I don’t understand why devices such as wAP or cAP exists and who buys them if they have such problems in 802.11 compatibility. Consider using unifi or some enterprise equipment.

4

please check:

in wireless registration table rx signal strength of the client device before, during, and after the transfer test
in wireless registration table rx ccq (enable the column) before, during, and after the transfer test
in wireless registration table tx rate and rx table before, during, and after the transfer test
cpu usage before, during, and after the transfer test

please chare your wireless interface configuration tabs, be sure of enable advanced mode to see all the possible options and check for possible improvements

5

Here are results.
Before:
resources-before.PNG
During:
resources-during.PNG
After:
resources-after.PNG
Here are Wireless configuration tabs:
wlan-01.PNG
wlan-02.PNG
wlan-03.PNG
wlan-04.PNG
wlan-05.PNG
wlan-06.PNG
wlan-07.PNG
wlan-08.PNG
wlan-09.PNG
wlan-10.PNG
wlan-11.PNG
wlan-12.PNG
Security: WPA2 + AES

Download speed during test was less than 1 MByte per second. If turn on g-mode only the speed is stable over 2 MBytes per second.

6

I think this is an application layer issue, maybe something wrong with Atheros driver internal of RouterOS, different devices with differnet hardware has the same problems. 802.11n as AP is not working mode for all my Mikrotik devices (2011, 951, 435+R52Hn). While 802.11g mode is stable and works perfectly with all devices :slight_smile:

7

Lets continue :slight_smile: I take RB411 (as known this is not so powerfull device) and plug to it my R52Hn. RoutersOS 6.40.5, same wireless configuration, the results are the same (download speed less than 1 MByte/sec).
So… I have downloaded OpenWRT 15.0.1 and flashed it to my device. After kmod-ath9k were installed as WiFi card driver. OpenWRT basic wifi configuration: 802.11n AP, 17 dBm, WPA2-PSK + AES.
Test results: Same laptop + OpenWRT 15 RB411 + R52Hn, 802.11n mode, 130 MBit connection - download speed near 3-4 MBytes/sec. RB411 CPU utilization near 6%.
My conclusion is that all issues of WiFi on Mikrotik devices are totaly software problem.
openwrt-wifi-1.PNG

8

Interesting findings :slight_smile: @mikrotik We need ROS optimization…
When mikrotik hardware works better with 3rd parties software :frowning:

9

Sorry about the delay in responding:


it catches my attention the high rx llvel during the test -16dbm is a pretty high level !!

in wireless tab please try enabling wmm support, multicast helper, and keep alive frames
in advanced tab please try frame life time 0, disconect timeout 0,
in HT tab please try guard interval long and uncheck AMPDU priorities 5, 6 and 7

i hope that setting can help you to improve the situation

10

You can try this :

WMM enabled - YES
Normaly you need to do test scan frequency and try with frequency non perturbe (in your case do not use auto ! for example choose 2437 (channel 6))
wireless protocol - 802.11
in advanced -
HW.Protection mode - rts cts
adaptive noise imunnity -ap and client mode
and saw what you are russian you can view video sur youtube webinar for wireless: https://youtu.be/Cy3zYczI-8Y

11

Thank you for respond.
Done! Nothing to changes, download speed less that 1 MByte/sec :frowning:

12

Thank you! But as you can see on top of this topic more of your recomended settings was done. The channel was selected as the most avaliable for my situation of course. HW protection mode does not help. Download speed still less than 1 MByte/second (usualy about 500-600 KBytes/sec) :frowning: All traditional recomendations for ROS as AP was done. I’d like to pay attention to something wrong is more deeper than user’s settings of ROS, something wrong with WLAN driver or like this, OpenWRT on same hardware works perfectly.

13

They are. Mikrotik is aware of it and they are doing nothing with this. Wireless is very weak point in Mikroitk. They worked for ages to obtain good throughput in 802.11n and now it works ok, but only for NV2 protocol and between Mikroitk devices only. Still there are issues with 802.11ac throughput (Ubiquiti works much better). Mikrotik is great if you consider wired routers, but if you want to have good wireless i wouldn’t buy their devices.

14

maybe routeros have issues with that “old” card.

i have tested following models with good wifi performance:
rb951-2n (only drawback was the coverage because off to little tx power)
rb951Ui-2Hnd
rb951G-2hnd
hap lite
hap ac lite
wap
wap ac

15

I have rb951G-2hnd and situation is the same with my laptop. Maybe something wrong with my laptop, but there are issues only with Mikrotik devices, all others works perfectly.

16

Your laptop is OK. There is a problem with Mikrotik wireless drivers when they are connected with some Broadcom chips: http://forum.mikrotik.com/t/xiaomi-phone-low-wifi-tx-rate/93622/1

17

it is not necessary to generalize

the related problem manifest as no negotiating 802.11n data-rates, that is limiting to 54mbps that is 22mbps of real thoroughput, way beyond this case results

18

solved on 6.40.8 (bugfix old bridges) and 6.42.1 (current new bridges)

19

The problem is not fixed for me, i have 3 hap AC units with latest 6.45.8 and the problem still exists on 2.4Ghz interfaces.
I had to disable 802.11n altogether on the 2.4Ghz interface ( 5Ghz is fine using ac band mode ) as i was having lots of weird symtoms turned out to be the 802.11n on the 2.4Ghz interface. http://forum.mikrotik.com/t/winbox-empty-resolved/105828/5