Strange issue with WiFi speed on R52n

RouterOS Wireless Networking
1

Hi all,
Recently I’ve faced quite strange problem with wireless speed on my R52n card. I use 433AH routerboard running 6.38.5 version of RouterOS. My hardware setup is as following:

[ISP provided Zyxel ADSL router LAN] → [Mikrotik LAN] → WiFi clients _The problem is as following:

  1. If I connect with my computer directly to ISP Zyxel over 5GHz WiFi, then I get ~70Mbps speed on speedtest.net
  2. If I connect to my Mikrotik 5GHz (R52n) then I get only ~40Mbps

    What I have tried:
  3. Disable WiFi on Zyxel, so it does not interfere with Mikrotik. Problem remains.
  4. Add Mikrotik to ISP router’s DMZ config, so I do not have double NAT config. Problem is the same.
  5. Connect my computer with LAN cable to Mikrotik. In that case I get ~70Mbps as supposed. LAN and WiFi use absolutely the same firewall rules. There are not differences.
  6. Tested speed between my computer and Mikrotik R52n card by using Mikrotik’s tool “BTest”. In that case I can reach up to ~110Mbps. Means there are no problems with WiFi card or computer drivers.

    So it seems like double NAT is not a problem, WiFi signal is not interferring, firewall can process traffic at requited speed (after testing with LAN), WiFi can get speed up to ~100Mbps. But there is no way I get 70Mbps on speedtest.net while I’m connected to Mikrotik’s WiFi.
    Any suggestions what to test or check? Maybe adjust some settings?

    Just in case I’m pasting my WiFi config:_
Flags: X - disabled, R - running 
 0  R name="wlan1" mtu=1500 l2mtu=1600 mac-address=##:##:##:##:##:## 
      arp=enabled disable-running-check=no interface-type=Atheros AR92xx 
      radio-name="############" mode=ap-bridge ssid="xxxxxx" area="" 
      frequency-mode=manual-txpower country=no_country_set antenna-gain=0 
      frequency=5200 band=5ghz-a/n channel-width=20/40mhz-eC 
      scan-list=default wireless-protocol=802.11 rate-set=default 
      supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps 
      supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,
                    54Mbps 
      basic-rates-b=1Mbps basic-rates-a/g=6Mbps max-station-count=2007 
      distance=indoors tx-power-mode=default noise-floor-threshold=default 
      nv2-noise-floor-offset=default vlan-mode=no-tag vlan-id=1 
      wds-mode=disabled wds-default-bridge=none wds-default-cost=100 
      wds-cost-range=50-150 wds-ignore-ssid=no update-stats-interval=disabled 
      bridge-mode=disabled default-authentication=no default-forwarding=no 
      default-ap-tx-limit=0 default-client-tx-limit=0 wmm-support=disabled 
      hide-ssid=no security-profile=secprof1 wps-mode=disabled 
      station-roaming=enabled disconnect-timeout=3s on-fail-retry-time=100ms 
      preamble-mode=both compression=no allow-sharedkey=no 
      station-bridge-clone-mac=00:00:00:00:00:00 ampdu-priorities=0 
      guard-interval=any 
      ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,
                 mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15 
      ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7 
      tx-chains=0,1 rx-chains=0,1 amsdu-limit=8192 amsdu-threshold=8192 
      tdma-period-size=2 nv2-queue-count=2 nv2-qos=default nv2-cell-radius=30 
      nv2-security=disabled nv2-preshared-key="" hw-retries=7 
      frame-lifetime=0 adaptive-noise-immunity=none 
      hw-fragmentation-threshold=disabled hw-protection-mode=none 
      hw-protection-threshold=0 frequency-offset=0 rate-selection=advanced 
      multicast-helper=default multicast-buffering=enabled 
      keepalive-frames=enabled pci-info="00:13.0"
2

Hi again,

I still haven’t found any solution to this issue. Could somebody please tell me if information in my original post was no very clear. I would really like to have at least some ideas of where to search for a problem. So far nothing helps.

3

Do you have multiple antennas on the routeboard and Have u enabled both chains?

4

Hi,

Thanks for your reply. Yes, I use two antennas on R52n, but they are standard small “pigtails”. Also I have enabled both chains. Once again, I have over 100 Mbps with the same card and same antennas when using BTest. So I suppose hardware is capable of passing through at high speed. Only difference is that I use BTest with udp packets. I can’t test with tcp, because BTest just crashes.

5

Hi,

On what speed is the ethernet connecting on the network?

if you have 100Mbps and 1Gig ports mixed, enabling flow control on the ports should solve that issue.

Also the 433 doesn’t have a very powerful cpu.

https://routerboard.com/RB433

6

Hi,
Yes, I know that CPU is not most powerful, but it is capable of providing correct speed when I use my computer connected to router on Eth port. WAN connection and my computer connections are Gbit. The problem is on WiFi, it does not seem to provide enough speed from Eth1 port.