High Rate of STP topology changes on port

hmc250000
Getting noticed

High Rate of STP topology changes on port

we are seeing "High Rate of STP topology changes on port" when we connect a Meraki switch to a Cisco network. Both cisco and Meraki use the RSTP spanningtree mode. In the switch settings we can change the root bridge setting to a Meraki switch only however the root bridge (core) is a cisco switch. this happens when we need to make the port a trunk port (access ports seem to work fine). Anything we can do to correct the spanningtree issue? 

12 REPLIES 12
ww
Kind of a big deal
Kind of a big deal

Re: High Rate of STP topology changes on port

hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

Thanks but sorry to say this sucks. Meraki did a good job making user friendly network devices. however it could not make it work more efficiently with RSTP connecting to Cisco switches?

UCcert
Kind of a big deal

Re: High Rate of STP topology changes on port

Hi @hmc250000 , you’ll need to configure your Cisco network for MST. Once done it’ll play nicely.  It’s literally a couple lines of config.

Darren O'Connor | uccert.co.uk
https://www.linkedin.com/in/darrenoconnor/

I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.
hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

It's a pain having to make that change on about 30 switches just to add 1 or 2 meraki switches.

 

WirelesslyWired
Meraki Employee

Re: High Rate of STP topology changes on port

if youre using rapid-pvst just include vlan 1 in the trunk between the Catalyst upstream switch and MS. This will ensure that the stp formatted BPDU makes it to the RSTP process and prune any unused VLANs from the trunk

CCIEw# 45253 / CWNE# 249 / Senior Technical Marketing Engineer - Meraki MS Product
hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

vlan 1 is included, I did not remove it.

Bruce
Kind of a big deal

Re: High Rate of STP topology changes on port

@hmc250000, what @WirelesslyWired said is true, so long as the Meraki switches are not 'between' two Cisco Catalyst switches - i.e. you don't have Catalyst -> Meraki -> Catalyst (Root Bridge). As well as including VLAN1 on the trunk, I believe it also needs to be the Native VLAN, and you need to make sure the Cisco Catalyst is the Root Bridge. I believe the Cisco Catalyst sends a Standard BPDU on the Native VLAN, for VLAN 1 (its a bit more complicated than that, but ultimately that's the easiest configuration to achieve).

 

If you do have the Meraki switches between the Catalyst switches then the only real option is to move the Catalysts to MST as has already been said.

hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

the Meraki Sw is on the edge and not inbetween Cisco switches. Not sure if I'm doing anything wrong here but this is what it looks like.

 

 

MS_SW.PNG

Bruce
Kind of a big deal

Re: High Rate of STP topology changes on port

What is showing up in the event log? If Port 25 is your only connection to the Cisco Catalyst switches then in general you shouldn’t be seeing that error. Check the STP Bridge Priority for the Meraki switches, by default it is 32768, make sure that the root bridge Cisco Catalyst has a priority lower than this on VLAN 1, like 8192 (the Cisco Catalyst defaults to 32768 too).

hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

Yes, the root bridge has a lower priority and is the core switch in the Cisco network. The bridge settings in the Meraki switch settings were not changed. We cannot change it to a cisco switch anyway.  Sorry failed to mention we have plugged in 2 Meraki switches. Both are connected to separate cisco switches on the edge.

 

These are the latest events I'm seeing.

 

7 12:45:06 Port STP change
Port 13 designated→disabled
Oct 7 12:45:06 Port status change
port: 13, old: 1Gfdx, new: down
Oct 7 12:44:48 Port STP change
Port 13 disabled→designated
Oct 7 12:44:48 Port status change
port: 13, old: down, new: 1Gfdx
Oct 7 12:44:25 Port STP change
Port 7 disabled→designated
Oct 7 12:44:25 Port status change
port: 7, old: down, new: 1Gfdx
Oct 7 12:44:25 Port STP change
Port 5 disabled→designated
Oct 7 12:44:25 Port status change
port: 5, old: down, new: 1Gfdx
Oct 7 12:44:25 Port STP change
Port 2 disabled→designated
Oct 7 12:44:25 Port status change
port: 2, old: down, new: 1Gfdx
Oct 7 12:44:24 Port STP change
Port 1 disabled→designated
Oct 7 12:44:24 Port status change
port: 1, old: down, new: 1Gfdx
Oct 7 12:44:21 Port STP change
Port 7 designated→disabled
Oct 7 12:44:21 Port status change
port: 7, old: 1Gfdx, new: down
Oct 7 12:44:21 Port STP change
Port 5 designated→disabled
Oct 7 12:44:21 Port status change
port: 5, old: 1Gfdx, new: down
Oct 7 12:44:21 Port STP change
Port 2 designated→disabled
Oct 7 12:44:21 Port status change
port: 2, old: 1Gfdx, new: down
Oct 7 12:44:20 Port STP change
Port 1 designated→disabled
Oct 7 12:44:20 Port status change
port: 1, old: 1Gfdx, new: down
Oct 7 12:44:10 Port STP change
Port 3 disabled→designated
Oct 7 12:44:10 Port status change
port: 3, old: down, new: 100fdx
Oct 7 12:44:07 Port STP change
Port 3 designated→disabled
Oct 7 12:44:07 Port status change
port: 3, old: 100fdx, new: down
Oct 7 12:44:01 Port STP change
Port 7 disabled→designated
Oct 7 12:44:01 Port status change
port: 7, old: down, new: 1Gfdx
Oct 7 12:44:01 Port STP change
Port 5 disabled→designated
Oct 7 12:44:01 Port status change
port: 5, old: down, new: 1Gfdx
Oct 7 12:44:01 Port STP change
Port 1 disabled→designated
Oct 7 12:44:01 Port status change
port: 1, old: down, new: 1Gfdx
Bruce
Kind of a big deal

Re: High Rate of STP topology changes on port

What is on those ports? It looks like you are seeing the STP changes because the ports are going up and down - they’re flapping. Every time a port goes up or down you see the corresponding change in STP, either moving to designated, or moving to disabled.

hmc250000
Getting noticed

Re: High Rate of STP topology changes on port

Access points are plugged into those ports. The AP's worked fine when they were plugged into the Cisco switches.

 

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