RSTP Role Changes Disabling Ports – No BPDU Events Logged

[agionet]

We're experiencing frequent RSTP role changes, but no BPDU events are logged anywhere in the Dashboard.

All of my client access ports have RSTP & BPDU enabled, example config:

The links between switches are set to trunk ports, example config:

We have some additional trunk ports for devices that need to access multiple VLANs, e.g., wireless access points, meeting room devices, NAS, hypervisors, example config:

Network Setup:

• Core Switch: MS225-1 (STP Root, Priority 4096)
• Other Switches: MS225-2, MS130-2, MS250-1
• Client VLANs: VLAN 10 (Management), VLAN 30 (Desktops), VLAN 50 (Guest Wi-Fi), VLAN 90 (Staff Wi-Fi)
  
  

What I’ve Checked:

• No BPDU Guard events in network-wide logs
• VLANs match on switches
• Uplinks are stable, no flapping or CRC errors

[michalc]

You are experiencing port flapping on port 17 and 21. Please verify physical layer. I recently described the event logs seen in my other post.

[agionet]

Hi Michalc, 

The flapping is happening to many ports across all switches. End users are complaining about slow download speeds, and the dashboard throughput tests to the core switch (SW-MS225-1) only show 10Mbps when the MX84 dashboard throughput test shows 250Mbps, which prompted me to review the event logs. 

The only other thing I can think of is these end user ports are connected to Microsoft Surface docks - could the flapping be happening when users disconnect or connect their laptops to the docks? 

[IvanJukic]

Hi @agionet ,

"Microsoft Surface docks - could the flapping be happening when users disconnect or connect their laptops to the docks? " 

I would say would be the likley culprit of the logs. However, given you have mentioned the End users complaining about slow speed. I'd propose you give @DarrenOC 's suggestion a go. Ensure RSTP Root is set correctly. 

https://documentation.meraki.com/MS/Monitoring_and_Reporting/Loop_and_MAC_Flap_Detection_on_MS

[ww]

Switch throughput test are always low thats not a good indication. 

Are the users complaining connected wired or wireless?

After work hours, Connect a client wired to a switch and do a speed test, also connect a client to the mx and do a speed test .

[agionet]

Users complaining both wired and wireless

[DarrenOC]

On first glance stp guard is set to disabled on the uplinks between your switches

set to root guard from core to edge and then loop guard on the links back to your core.

if you look at the topology page do you see anything out of the ordinary?

[GIdenJoe]

I wish Meraki would suppress the link down -> RSTP disabled and link up -> RSTP designated on portfast/edge ports cause these just flood the eventlog for no real benefit.  It is already enough to have the link down link up on these ports.