(false) Loop Protection

[rkelly1]

I don't think I have a loop but maybe I'm missing something...

WS-24-400B, 1.2.0rc7, lot of stuff plugged in at the NOC and has been running flawless for a couple of months. Upgraded to 1.2.2 final last night and two ports interchangeably keep getting shut down for 180s with the log saying "Loop protection: disabling port 19 for 180 seconds" , this will come back on and a different port will be disabled. It cycles between these two ports. The two ports happen to be on a different vlan.

Downgrade to 1.2.0rc7 and it goes away.

What am I missing?

[sirhc]

Not sure please post your config Tabs here primarily Ports, VLAN, Device Config Tabs and do you have an IP's assigned to VLANs and or Trunking going on?

[rkelly1]

No IP's assigned to VLANS and no Trunking. I may have figured it out and maybe you can provide some input.

Tower router has backhaul link on port 1, all tower APs on port 3. On this router I have a bridge which includes ports 1 and 3.

On WS -
Backhaul radio on port 20 and port 21 goes to port 1 on router. These are on vlan 19.
Tower APs are on ports 14-17 and port 13 goes to port 3 on router. These are all on vlan 20.

Is it sensing a loop because of the bridge on the router? I just removed the backhaul from the switch and plugged it into a POE brick, then updated the switch to 1.2.2 and I'm not getting the loop error. Maybe it is a boneheaded loop?

We have some towers remaining with bridges on the routers (removing bridges soon) but would like to install netonix switches in the meantime. Is there a way have the backhaul and Tower APs powered from the switch with different Vlans but a bridge on the router without creating a loop? Or will I need to use the POE brick until the bridge is removed?

[sirhc]

Just to interject something here.

Last night I was playing around and noticed that Loop Protection will detect a loop across VLANs which is of course a FALSE loop detection.

SO you might just have to disable Loop Protection for that to work.

I plan to talk to Eric about this.

[rkelly1]

Thanks Chris. It sounds like false loop detection across VLANS may be the issue.

Let us know when resolution is planned for this as we like to have loop protection enabled...if possible.

[Eric Stern]

I tested this in the lab using 1.2.2. I set ports 4 and 5 on both switch to VLAN 200. The switches are connected to each other on port 1.

If I connect the switches on port 3 (VLAN 1) loop protection disables one of the ports, as it should.

If I connect the switches on port 4 (VLAN 200) loop protection does not kick in.

So, in general loop protection is working correctly with VLANs.

If someone can suggest a way to reproduce this problem I will look into it further.

[rkelly1]

Eric - See my post above with the example. Also, I think Chris was able to reproduce it.

[Eric Stern]

I don't think I have a loop but maybe I'm missing something...

WS-24-400B, 1.2.0rc7, lot of stuff plugged in at the NOC and has been running flawless for a couple of months. Upgraded to 1.2.2 final last night and two ports interchangeably keep getting shut down for 180s with the log saying "Loop protection: disabling port 19 for 180 seconds" , this will come back on and a different port will be disabled. It cycles between these two ports. The two ports happen to be on a different vlan.

Downgrade to 1.2.0rc7 and it goes away.

What am I missing?

The log says it disabled port 19, but you never mentioned port 19 when you described your configuration. Also, what is the other port that gets disabled?

[rkelly1]

I may have described the wrong vlan port set but the same result. I set up a different 8 port switch and a router for testing and here is the setup. These are the only items plug into the router.


Switch port 1 to internet
Switch port 2 to router port 1
Both of above ports on vlan1

Switch port 7 to router port 6
Switch port 8 to computer
both of above ports on vlan 99

On router, port 1 and port 6 are in a bridge
Prior to version 1.2.2, there was not an issue, everything ran fine, no errors, no drops, no loops.

1.2.2 and 1.2.3 indicate loop protection and shut down ports 2 and 7.

Router port 1 has vlan1, router port 6 has vlan 99. Bridge has no associated vlan.

My understanding is that I can use the vlans on the switch to basically create separate port groups for dividing up use of ports? Maybe I'm doing it wrong...

Thanks

[rkelly1]

Chris - Could you share your testing with Eric as well?

Rob