All of the sudden we have Loop Protection!

[jma]

This switch is on one of our sites.
There is nothing 'behind' that switch other than one AP for clients. That AP is in port 4.
The 'looping' port (port 3) goes to a PowerBeam M5400 (bridge) PTP that is connected to a AP (Sector Antenna) on another site. That is how we connect that site to the network.
That sector antenna is connected with yet another switch. That switch is getting internet from a PTP bridge. So the loop on that part could be coming from anywhere in our network if I am not mistaken?
It is a flat network. Never had this problem before. And only this switch is doing it.
We will change the PowerBeam and cable. And if it occurs again we will also replace the switch. After that, I will start searching again.
Thanks for your explanation and time.

[sirhc]

Not cable or power beam causing this.

If it is a false loop protection from something simply disable Loop Protection.

[jma]

Thanks for that confirmation. Am I correct in thinking that if we disable the loop protection on that switch only, and the error is there for a reason, we are going to see the loop protection time out on one of our other switches?
If that is correct, I could check that way if it is actually a false loop protection?

[jma]

I have been searching and searching for two weeks now. Every single day I spend hours to try to figure out what is happening. We have replaced cables, devices, ets ...
It feels like searching for a needle in a haystack.

I really can not imagine that there is a loop in our network.
Yet every single day we have this loop protection at least one time on one of our switches. Sometimes a couple of times in a row in a very short period.
So this must have a reason.
I really don't want to disable loop protection on all our switches. I want to know where this is coming from.

When I disable loop protection on the single switch that we have the problem on, it starts on another switch.
Could you please tell me what exactly I have to search for?
Can this be due to one of following reasons?

- Flow control problem with one of our UBTN AirFiber bridges? (they are all flow control disabled, switch ports also flow control disabled for these ports)
- temporarily slower throughput on one of our bridges or switches? Can that cause a loop protection on one of our other switches?
- bad cable somewhere in the network
- bad switch?
- a NAT router that is connected with a cable to one of our switches (WAN side on our network, LAN side for the client)
- a CPE from a client (WAN wireless connected to our network, LAN side for the client)

[sirhc]

- Flow control problem with one of our UBTN AirFiber bridges? (they are all flow control disabled, switch ports also flow control disabled for these ports)

Not

- temporarily slower throughput on one of our bridges or switches? Can that cause a loop protection on one of our other switches?
-

Not

- bad cable somewhere in the network

Not

- bad switch?

Not

- a NAT router that is connected with a cable to one of our switches (WAN side on our network, LAN side for the client)

Remotely possible

- a CPE from a client (WAN wireless connected to our network, LAN side for the client)

Remotely possible but I have never seen this and at my WISP all residential services are setup like this.

Loop protection sends a packet out each port over and over again with information on the switch and the port that it came from. If that packet returns to that same switch on any port even the same port it will be seen as a loop and trigger the event.

I have Loop Protection turned on every switch in my WISP network and just do not see any Loops or False Loops but I run a routed network and use VLANs at each tower from switch to AP.

Watch the 1.5 hour video which is a tour of my WISP and how my network is setup.
https://www.youtube.com/watch?v=8JvBEAD4MFM

If your running a large flat network things like this happen and it is hard to find the issue which is why I moved away from large layer 2 segments years ago.

[jma]

@sirhc Thank your very much for your responses.
I will watch the video for sure. And I think I will follow your advice about moving away from a large flat network.