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notpoetry
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RB951-2n WiFi disconnecting how to figure out root cause?

Mon May 02, 2022 9:40 pm

Have a RB951-2n on latest software version (also updated the router board firmware) and WiFi will just disconnect on the client device. I have restarted the device multiple times to make sure it's all updated (you need to to upgrade router board firmware). No pending updates.
How can I figure out the root cause of the disconnection? Signal is great always over 90%.
Device that are connected are mostly a few windows laptops and mobile phones. Disconnecting time is just random.
Is it possible to enable some kind of debug mode so I can see the disconnect reason on the device?

Any recommendation to change WiFi settings so it will perform better (or it is just a limitation of the device too slow/too cheap?).

Current simple configuration. Yes I have setup the country code just removed from screenshot.

Image

Here is my configuration it's very simple (removed country, ssid, device name from post but it's configured on the device)
# may/02/2022 by RouterOS 7.2.2
# software id = 7QGY-T6VT
#
# model = 951-2n
# serial number = 
/interface bridge
add name=bridge1
/interface wireless
set [ find default-name=wlan1 ] antenna-gain=1 band=2ghz-g/n country= \
    disabled=no frequency=auto installation=indoor mode=ap-bridge ssid= \
    wireless-protocol=802.11 wps-mode=disabled
/interface list
add name=WAN
add name=LAN
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa-psk,wpa2-psk group-ciphers=\
    tkip,aes-ccm mode=dynamic-keys supplicant-identity=MikroTik \
    unicast-ciphers=tkip,aes-ccm
/interface bridge port
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5
add bridge=bridge1 interface=wlan1
/ipv6 settings
set disable-ipv6=yes
/interface list member
add interface=ether1 list=WAN
add list=LAN
add interface=bridge1 list=LAN
/interface ovpn-server server
set auth=sha1,md5
/ip address
add address=192.168.1.5/24 interface=bridge1 network=192.168.1.0
add address=192.168.1.4/24 interface=ether1 network=192.168.1.0
/ip dhcp-client
add disabled=yes interface=ether1
/ip dns
set servers=1.1.1.1,1.0.0.1
/ip service
set telnet disabled=yes
set ftp disabled=yes
set www disabled=yes
set ssh disabled=yes
set api disabled=yes
set api-ssl disabled=yes
/ip upnp
set enabled=yes
/ip upnp interfaces
add interface=bridge1 type=internal
add interface=ether1 type=external
/system clock
set time-zone-name=
/system identity
set name=
/system leds
set 0 disabled=yes
/system routerboard settings
set auto-upgrade=yes
 
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bpwl
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Re: RB951-2n WiFi disconnecting how to figure out root cause?

Mon May 02, 2022 10:21 pm

1. Reason for disconnect should be in the LOG. For a more extended log add "/system logging add topics=wireless"

2. WAN and LAN with routing should be in different subnets. Now ether1 and bridge1 are both in subnet 192.168.1.0/24
If you want one subnet for all (as you clearly define the rest as such) then "bridge" mode should be used. All ethernet and WLAN ports will be on the bridge, which will get one IP address. Bridge will be LAN member, so is everything else also LAN. The LAN/WAN transition happens at the 192.168.1.1 router, not here.

3. Check signal strength and interface rate (raw speed) in the "Wireless Registration table", not on the client device.
I see antenna gain values of 1.5 (2) hAP or 2.5 (3) RG591UI/G in the MT specs. Unclear to me how you still could set 1 as antenna gain. Minimum should be enforced, and is 2 or 3.

3. Performance hint: avoid "tkip", unless needed. ("tkip" is slow)
 
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chechito
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Re: RB951-2n WiFi disconnecting how to figure out root cause?

Tue May 03, 2022 12:40 am

beware RB951-2n has the less powerful TX radio of all the product line, even less powerful than haplite (5db, less power), also worst RX sensitivity
 
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anav
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Re: RB951-2n WiFi disconnecting how to figure out root cause?

Tue May 03, 2022 3:13 pm

Modern devices are simply allergic to MT wifi5.
 
notpoetry
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Re: RB951-2n WiFi disconnecting how to figure out root cause?

Tue Sep 06, 2022 9:33 pm

Should I just trow away this device? It's ridiculous that my old Linksys WRT54G is performing better than RB951-2n.
It's so terrible I am just not using my wireless anymore. At some specific times I just keep getting disconnected for no reason. Will look in the logs and post here later.

I am just too stupid to configure this properly? I would like to configure just wireless 802.11 that will be stable and will give me maximum throughput. I was expecting at least double the speeds as I was getting on my WRT54G as that is using just 2.4Ghz 802.11 b/g and that is the limit for that device. I was expecting 2.4Ghz 802.11 n will give me higher speeds I am just thinking about this wrong? I do understand that RB951-2n has a terrible antenna (just internal) that is probably the limit for this device right? but in the space I am using it should not make a difference as it's such a small house.

Images during speedtest down/up for @bpwl
Image Image

Anyone seeing anything really stupid from this screenshots below (running speed test on my phone at the time of the screenshots and getting terrible speeds):

Image Image Image Image Image Image Image Image Image Image Image Image
 
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bpwl
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Re: RB951-2n WiFi disconnecting how to figure out root cause?

Wed Sep 07, 2022 12:06 am

Now I see it is the obsolete 50mW AP, with single chain. Indeed a very weak transmitter. Even as the regulatory domain allows for 19dBm (see interface status), the device only goes up to a lower TX power of 10dBm reported.

- single chain will only give 72Mbps interface rate for 802.11n at MCS07 , which it can only send with 9dBm as TX power documented. Receive sensitivity of -67dBm is for a weak receiver
- even a hAP Lite does substantially better, and that the weakest current device, (not recommended as it will not follow newer ROS releases)
- I would never put ROSv7 on such obsolete device. Return to something like 6.45.8 (I know this one works well, somebody tested to just find which one was the highest good one for a small MT router. I forgot the exact version, but it is close as 6.47.9 was bad.)
- still any disconnect reason should be in the log !
- The 2.4GHz band is usually overcrowded, and this device is 10dBm below the other AP's. This signal is easily overpowered by others, that might see it below the noise level.

Do not underestimte the WRT54G , it is only 802.11g but has good power and has good antenna. (gain is not in the specs). I handed out hundreds of those to "home" workers. If using the ethernet-ports as switch be aware that disabling the DHCP server does not disable the DHCP server, but makes it transmit DHCP NAK to every request. (can bring down local part of the corporate network)
WRT54G will outperform your RB951-2.

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