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bzc0fq
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RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Tue Jun 28, 2022 7:54 pm

Hi,

I have an issue with RBmAPL-2nD device (actually two devices working as a bridge).

First device (named VideoBr-LAN) works in bridge mode, second device (named VideoBr-WAN) works in station bridge mode.
Both device suppose to provide connectivity between Video Indoor Station and Video Door Station and in fact they did until today morning.
Today I had to power off/on both devices and after this, I have found out lots of ping timed outs while testing connectivity between my laptop and Video Door Station.
Also Video Indoor Station does not work with Video Door Station any more (reports time out issue). Problem disappears when Video Indoor/Door Stations are directly connected bypassing Mikrotik bridge.

I can see two reasons for this:
1) lost - unsaved Mikrotik parameter, - however possible - I tried restoring config backup of both devices... no luck this time... the same issue remains on restored systems (backup is 2 moths old).
2) hardware issue - very unlikely - as far as I was able to test both devices they work fine... as so did for last 2 months.


Configuration of Mikrotik devices looks as bellow:
# jun/28/2022 17:58:09 by RouterOS 6.48.6
# software id = DZY4-QSR8
#
# model = RBmAPL-2nD
# serial number = FAC90F7DAC11
/interface bridge
add name=bridge1
/interface wireless
set [ find default-name=wlan1 ] band=2ghz-onlyn channel-width=20/40mhz-Ce country=poland default-authentication=no disabled=no frequency=auto mode=bridge ssid=VideoBr \
    wireless-protocol=802.11
/interface list
add name=WAN
add name=LAN
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa2-psk mode=dynamic-keys supplicant-identity=MikroTik wpa-pre-shared-key="xxx" wpa2-pre-shared-key=\
    "xxx"
/interface bridge port
add bridge=bridge1 interface=wlan1
add bridge=bridge1 interface=ether1
/interface bridge settings
set allow-fast-path=no
/ip neighbor discovery-settings
set discover-interface-list=!dynamic
/interface list member
add list=LAN
add interface=ether1 list=WAN
add interface=wlan1 list=LAN
/interface wireless access-list
add mac-address=DC:2C:6E:BE:3C:78
/ip address
add address=192.168.101.33/24 interface=wlan1 network=192.168.101.0
/ip dns
set servers=192.168.101.1,192.168.101.254
/ip route
add distance=1 gateway=192.168.101.254
/system clock
set time-zone-name=Europe/Warsaw
/system identity
set name=VideoBr-LAN
/system package update
set channel=long-term


The second device export bellow:

# jun/28/2022 18:00:40 by RouterOS 6.48.6
# software id = CUFT-7AXP
#
# model = RBmAPL-2nD
# serial number = FAC90F4439B2
/interface bridge
add name=bridge1
/interface wireless
set [ find default-name=wlan1 ] band=2ghz-onlyn channel-width=20/40mhz-XX country=poland disabled=no mode=station-bridge ssid=VideoBr wireless-protocol=nv2-nstreme-802.11
/interface list
add name=WAN
add name=LAN
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa-psk,wpa2-psk eap-methods="" group-ciphers=tkip,aes-ccm mode=dynamic-keys supplicant-identity=MikroTik unicast-ciphers=\
    tkip,aes-ccm wpa-pre-shared-key="xxx" wpa2-pre-shared-key="xxx"
/interface bridge port
add bridge=bridge1 interface=wlan1
add bridge=bridge1 interface=ether1
/interface bridge settings
set allow-fast-path=no
/ip neighbor discovery-settings
set discover-interface-list=!dynamic
/interface list member
add interface=wlan1 list=WAN
add interface=ether1 list=LAN
/ip address
add address=192.168.101.32/24 interface=bridge1 network=192.168.101.0
/ip dhcp-client
add interface=bridge1
/ip dns
set servers=192.168.101.1,192.168.101.254
/ip route
add distance=1 gateway=192.168.101.254
/system clock
set time-zone-name=Europe/Warsaw
/system identity
set name=VideoBr-WAN
/system package update
set channel=long-term

The output of ping command looks like this:


Request timed out.
Reply from 192.168.101.30: bytes=32 time=3ms TTL=64
Reply from 192.168.101.30: bytes=32 time=2ms TTL=64
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Reply from 192.168.101.30: bytes=32 time=15ms TTL=64
Reply from 192.168.101.30: bytes=32 time=2ms TTL=64
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Request timed out.
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Request timed out.
Request timed out.
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Reply from 192.168.101.30: bytes=32 time=2ms TTL=64
Reply from 192.168.101.30: bytes=32 time=1ms TTL=64
Reply from 192.168.101.30: bytes=32 time=2ms TTL=64
Reply from 192.168.101.30: bytes=32 time=2ms TTL=64
Reply from 192.168.101.30: bytes=32 time=228ms TTL=64
Request timed out.
Request timed out.

Could anybody advice on how to troubleshoot this issue further please?

Thanks!

PS.
I just realized that config file for the second device was incorrect.... now a correct one is in place.
 
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bpwl
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Re: RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Wed Jun 29, 2022 12:09 am

What has changed before and after the power off/on ?

Well very probably the wifi connection channel.

1. On the "bridge", setting "frequency=auto", is saying: I don't care , MT device you are free to pick whatever you like. I hope the MT makes a smart decision on this, but the MT decides something based on whatever it sees in the wifi-ether at power-on time. There are not even channel lists to learn the Mikrotik about the troublesome channel overlaps in 2.4 GHz band.
2. Using 40 MHz wide channel (Ce) is likely to create adjacent channel interference in the 2.4 GHz band. Even if it sticks to the 1-6-11 selection)
3. Previous random selection ("auto") might have been accidently better than the current one. SCAN ( + Snooper, Freq Usage, Wireless Sniffer) the environment and do make a wise "non-auto" channel selection, based on those measurements. (The 2nd MT, station-bridge will just follow the 1st "bridge" channel)
 
bzc0fq
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Re: RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Wed Jun 29, 2022 1:35 am

What has changed before and after the power off/on ?

Very good question :)

Basically what I did was powering off and on all the devices in one rack... this included Aruba POE switch that powers up Video Indoor Station and VideoBr-LAN, and Hikvision POE switch that powers up Video Door Station and VideoBr-WAN.
I did not do this 'in a clean way' just turn off/on UPS. I did not expect issues... of-course I had a backup configuration secured on the server :D (at that time i thought I had working copy backed up... but now, I am not so sure...)

I have checked with WIFI Monitor (after reboot, when I identified the issue) channels allocation and there were no interference between the devices I use at home (other devices signals - outside of the building - were so week we can exclude them from further discussion). I did some tests with different channels, channels bandwidth width and wireless protocols, but not significant changes were observed. Basically the same issue remains with all settings I have tested.

Now, I am out of new ideas on how to diagnose this further.
 
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bpwl
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Re: RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Wed Jun 29, 2022 10:54 am

LOG and Wireless "Registration Table" entries (detail mode) should help in verifying if the wifi is the weak link here. (eg Tx/Rx CCQ, ratio "Tx/Rx Frames" versus "Tx/Rx HW Frames" )
Other possible interrupts can come from (R)STP on the bridge: spanning tree change, root bridge election
 
bzc0fq
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Re: RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Wed Jun 29, 2022 12:21 pm

LOG and Wireless "Registration Table" entries (detail mode) should help in verifying if the wifi is the weak link here. (eg Tx/Rx CCQ, ratio "Tx/Rx Frames" versus "Tx/Rx HW Frames" )
Other possible interrupts can come from (R)STP on the bridge: spanning tree change, root bridge election

Thanks for helping... but finally I found what the issue was.

I forgot to mention I had also turned 'Extend on' switch OFF after I powered Hikvision POE switch off (Ethernet cable is 92m long between Hikvision POE switch and Video Door Station so is close to its limits).
This morning I have turned it ON which resulted in increasing ping times to average 2ms but getting rid of timeouts.
This extended operation distance to 250m but reduced Ethernet speed to 10Mb/s which is still sufficient for one video stream.

I remember I have turned this magic switch on and off but cannot remember I have done this while switch was powered on or not, so maybe it did not take effect when it was switched on working device.
What is more confusing when I bypassed bridge (both mAP) everything worked fine having switch in BOTH ON and OFF positions.

Anyway... issue solved.
 
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bpwl
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Re: RBmAPL-2nD <--- bridge ---> RBmAPL-2nD issue

Wed Jun 29, 2022 3:46 pm

Ethernet cable is 92m long between Hikvision POE switch and Video Door Station so is close to its limits).
Hmmm.... never considered https://mikrotik.com/product/gper ????

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