Loop detection

[ColoCenter]

Hello,

I have a ws-6-mini that is acting up. A port that is connected to a ubnt powerbeam gives at random these errors:

Apr 15 17:23:07 Loop protection: detected loop from port 3 to port 3, disabling port 3 for 180 seconds
Apr 15 17:26:09 Loop protection: re-enabling port 3

There is definitly no loop. And i exchanged the cable between the switch and the powerbeam also this afternoon. The powerbeam is being powered by the switch.

The switch is running firmware 1.3.9. Spanning tree is not enabled.

Any suggestions what might cause this?

[sirhc]

There is no bug, your network is returning the BPDU packet from somewhere beyond port 3 back to port 3.

It can be a leaky VLAN or if you give customers Layer 2 access to your network and if they have an internal loop this will happen.

Misconfigured routers and switches that leak BPDU packets can cause this as well.

You either need to find out what is passing this BPDU packet back triggering Loop Protection or simply turn it off. I run Loop Protection on all my towers and it does not mess up.

There is this new invention called a "search box"

A quick use of the handy search box looking for "Loop Protection" yields this post:
viewtopic.php?f=17&t=1459&p=12102&hilit=loop+protection#p12102

[ColoCenter]

First off, sorry i didn't use the search feature. Will do that next time.

But still wanted to report back, as i think i found the cause and it might help someone in the future. The network towards the problem switch was as follows:

Core router <-> Netonix ws-24-400 <-> Airfiber24 <-> Mikrotik CSR109-8 <-> Powerbeam m5 400 <-> ws-6-mini(1) <-> WS-6-mini(2) <->ws6-mini(3)

The WS-6-mini(1) was doing the loop detection on the port facing the mikrotik. So I didn't trust the mikrotik and replaced it also with a WS-6-mini. Enabled the loop detection again on the affected ws-6-mini(had disabled it for the mean time). And now everything is running fine again. Not sure what was happening, but the mikrotik definitly had something to do with it.

[sirhc]

Thanks for reporting back.