STP - Stopped receiving BPDUs with loop guard enabled

[Sweemz]

Hi All,

I hope we are well.

I’ve recently inherited a Cisco Meraki network following an acquisition and have noticed some alerts.

Edit - Added Network Topology/Switch overview (below)

Toplogy

Switch Overview

The network Consists of:

2 x MX105 in HA config.

5 x MS130-48P

4 x CW9166I

I've documented the network as best as possible.. (minus the access points) will re-review tomorrow and update asap.

Version 1

Version 2 - Since Reviewing Meraki Live Topology

- Root Ports mislabelled / corrected

DUG00-SW01 Port 51

DUG00-SW03 Port 50

The affected ports seem to be alternate uplink ports, so the network is still operational. I’d just like to understand the issue and get the network’s RAG status back to healthy.

Any thoughts on the best place to start troubleshooting?

Thanks in advance - let me know if you need more information!

[Sweemz]

Thank you @RWelch2 reading up now. Will look to action later today and will provide an update asap.

[joon12]

It looks like you’ve done a great job documenting everything so far! Since the affected ports are alternate uplinks, I’d start by checking STP settings, port roles, and any recent config changes. Have you noticed any looping or high latency issues?

[Sweemz]

@joon12 thank you.

Just done a review of the STP settings (see recent RWelch comment/my response) - all appears correct.

No looping and or high latency issues observed and or reported, no issues with connectivity/routing etc - the network is working, it's just alerting 🤷‍

[Sweemz]

Update as of 19:30 | 04/02/25 -

I'm happy to report that he remaining 'stp_loopguard_active' alert that was displaying for SW03 is now resolved 🙂

Looks like the Frimware Upgrade to MS 17.1.4 gave the switches a kick/reset.

Now.. for credit where credit is due, thank you to everyone that responded, this was a great experience for me on the Meraki forum.

Thank you for your time and for sharing your knowledge! 🫡

[RWelch-USA]

👏 👏 👏

[IvanJukic]

Good stuff man!!!