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Finding Loops/ STP

Posted: Wed Jan 24, 2018 8:01 pm
by jar
Hi All,
I'm trying to figure out how best to figure out where a loop is coming from on my network. See attached diagram

All routers are mikrotiks running 6.36.4 and netonix are WS-12-250-DC and running 1.4.8 (or newer). Each of the backhaul links are on a separate networks and we route using ospf.

If I turn both radios on BH1 (have connection, OSPF sees adjacency), then BH3 goes down. The netonix sense a loop and block the port.


Sep 7 04:05:03 STP: MSTI0: New root on port 4, root path cost is 80000
Sep 7 04:05:03 STP: set port 2 to discarding

I'm pretty sure that this is NOT a netonix issue (well maybe a config issue on my side). How would I go about troubleshooting this?

Re: Finding Loops/ STP

Posted: Fri Jan 26, 2018 9:07 pm
by mike99
Vlans and ports config would help. Maybe print screen or just the "show vlans" command via CLI and indicate which ports are use on each switch for those 3 links.

Re: Finding Loops/ STP

Posted: Mon Jan 29, 2018 7:28 am
by jefa
STP (and RSTP) is not vlan aware.

MST can be set up with separate instances for the vlans you use. If you only use the vlan for one link (besides the trunk to the router), you could simply disable spanning-tree for the interface to the link (both ends for each vlan/link).

Re: Finding Loops/ STP

Posted: Mon Jan 29, 2018 9:25 am
by mike99
Not VLAN aware but still protect again loop by blocking a whole port in the ring so loop shouldn't happen. He should get RSTP right first before adding more complexity with MSTP instances.

Re: Finding Loops/ STP

Posted: Tue Aug 24, 2021 5:10 pm
by mrmarria
This is old thread, I hope still being watched

I am having a very similar problem, what did you discover or have a solution?

My temporary solution was to take one end of a link off the netonix and put on regular poe supply, but I would like more information on the netonix settings or diagnostic to stop the actual (i suspect, invalid) loop detection.

Thanks