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MikroTik RouterBOARD SXT 5HPnD stopped seeing LAN devices on DtD switch

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N4SV
MikroTik RouterBOARD SXT 5HPnD stopped seeing LAN devices on DtD switch
  I have a MikroTik RouterBOARD SXT 5HPnD (SXT 5 High Power) configured on an older version of AREDN, and it's on a Netgear GS105E, the switch configured as a 2 Node 3 LAN switch per AREDN documents.  The Mikrotik is plugged into port 4.  Port 5 is my laptop for maintenance access.  On port 1 is an older Ubiquiti 2.4 GHz Air Grid, also on an older version of AREDN.  This setup has been working fine for several years and I have always been able to get an IP from the Mikrotik, or from the Air Grid if I move the laptop to one of the other LAN ports. 

One day I noticed the laptop could no longer see the Mitrktoik when on it's LAN port of the switch, and could no longer get an IP address from the Mikrotik.  I checked the port setup on the switch and all VLANs were still set correct on all ports, but to be sure it wasn't the switch I got another GS105E, configured it for 2 Node 3 LAN and switched it for the original switch, same issue, the laptop was not getting an IP from the Mikrotik.  At the same time the DtD was working OK for the Air Grid on port 1 and a laptop on LAN port 2.  Also the Air Grid on port 1 could no longer see the Mikrotik on port 4.

So to test I removed the Mikrotik from port 4, removed the laptop from port 5, and connected the laptop directly to the Mikrotik.  I found that everything worked fine, the laptop immediately got an IP from the Mikrotik and could see the AREDN interface of the Mikrotik (older version of AREDN simply because I hadn't gotten around to upgrading it for a while).  So the Mikrotik is doing AREDN mesh things fine, and over RF it sees it's sister MikroTik RouterBOARD SXT 5HPnD (SXT 5 High Power) and the nodes on that end of the link.  But once the Mikrotik is placed on a switch configured for VLAN2-DtD it doesn't see anything connected to the associated LAN port (RF side still appears to be worrking OK).  Its as though it stopped recognizing VLANs on the switch.  By the way, the mate MikroTik RouterBOARD SXT 5HPnD (SXT 5 High Power) on the other end of my short haul link was put up at the same time and still runs the same version of AREDN...older but seems to function fine on a similar DtD switch setup.

So, any thoughts, suggestions about what's up with the MikroTik RouterBOARD SXT 5HPnD (SXT 5 High Power) and it's seeming refusal to work as a DtD device?  I ended up trying about 4 different switches, all configured properly for VLAN use, and still same issue, the Mikrotik won't see anything on its LAN segment, while the Air Grid works fine on either segment of the DtD ports on the switch. 

73, Bill, N4SV
KD1HA
KD1HA's picture
Possibly a bad cable?
Possibly a bad cable comes to mind?  
N4SV
Network function issues with the Mikrotik
As far as I can tell all cables are working OK, I've switched them out to be sure.  One additional unusual functionality of this setup...the Mikrotik will no longer function on any Ethernet switch, not just one configured for VLAN 2 and DtD support.  I took a completely dumb Ethernet switch, no VLANS configured, and when the Mikrotik was plugged into one port and the laptop into another, the laptop still could not see the Mikrotik and hence could not get a DHCP address from it.  However, as stated before, if the laptop is connected to the Mikrotik via an RJ45 barrel connector (straight thru) it works fine.  I'm wondering of the POE injector on the Mikrotik is not producing sufficient voltage to power the Mikrotik when connected to an Ethernet switch, but is enough when a barrel connector is used to connect the same Ethernet cables together?
K7EOK
Out of the box question(s) ..
Out of the box question(s) ...

There is a ground lug on this device with a 1/4 inch spade connector (I think).  Did you actually ground it with a ground strap to earth ground?

Has there been a nearby thunderstorm recently?

I ask because I manage a site that had two SXT 5HPnD crap out at the same time, and I could not recover them no matter what I did.  I also thought it was a bad switch port but that wasn't the issue.  The SXTs were on the same pole as a mix of QRT5s and BaseBox5 devices, and only the SXTs died.  I've since replaced both antennas and added ground straps to the masts (better than nothing) to anything that has a ground lug.

Just saying ...   Ed
N4SV
Storm related issue potential
I can't rule this out as a possibility.  The failing unit is outside, but under cover of a metal awning, which doesn't mean it couldn't have been affected by a localized electrical storm.  It's something I have been thinking might be a possibility, but I don't believe the failure was directly after any storms.  The simple solution is to just replace it, but the failure mode has me scratching my head...how does it work fine with the laptop attached directly to the Mikrotik, but with the Mikrotik and the laptop on a dumb switch and the Mikrotik and laptop don't see each other?  Tried multiple switches, changed Ethernet cords, although I did not change the cord going to the Mikrotik, its about a 50 foot run and not easily replaceable.  And I haven't taken the Mikrotik down from its mounted location and done bench testing, with a different Ethernet cable sending POE to the Mikrotik...guess its time for me to bite the bullet and get it down and on the bench.

Thanks for the info, although not what I wanted to hear, seems like these may be overly susceptible to outside electrical issues.
KD1HA
KD1HA's picture
Have you considered moisture
Have you considered moisture creeping in?  MikroTik does a very good job with keeping the radios weather tight and we have many of them but somehow that water finds its way into the cables and equipment! If you can use gel-filled cables where long runs up towers and like you said difficult mounting locations. Well worth the extra money. Let us know what your resolve was! 
Denis
N4SV
Bench test awaits
Good point as well, while it is well under a metal awning its certainly possible some moisture has invaded the device or the Ethernet cable feed into the building.  Since I'll not discover for certain what the issue is till I get it on the bench, that test is pending.  I'll update with what I discover; maybe it will help someone else.  Thanks again, 73.  Bill

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