How can I locate the source of a spanning tree TCN?
04-17-2019 05:23 AM
We have S2500 MASs at our network edge. These switches connect IAPs, user wired computers, cameras, IP phones and some HVAC panels. Every so often I get notifications from Airwave that a topology change has occurred in one or another of our switch stacks. I don't know how to interpret these messages because, as far as I'm aware, no topology change has taken place. The way I understand it, there would have to be a physical or administrative breaking of a link to trigger a TCN. Is that correct? If so, I don't know why I'd be seeing these notifications when there's been no change that I can identify.
Switches are running firmware version 18.104.22.168; Airwave is version 8.2.7. Also, I see no such TCNs from our other network monitoring products (Solar Winds NPM and PRTG). Any help is appreciated.
Re: How can I locate the source of a spanning tree TCN?
04-24-2019 12:43 PM
We do have those configured on user ports; however, the port that keeps flushing the MAC table because of an alleged topology change is a point-to-point link between a switch in the wiring closet and a stand-alone switch in another room. The ports on that link do not have portfast, BPDUGuard and BPDU filtering enabled.