Spanning Tree Configuration Powerconnect 6248 and 3548

Question

I have a network configuration with several Powerconnect 3548s connected into a Powerconnect 6248. We have not changed any of the default Spanning Tree settings. We've noticed since the initial setup that the activity lights on all of the switches always seem to blink in unison like a hub rather than a switch. It had been a point of curiosity but never anything that caused much worry until recently when we've run into some connection issues related to VLANs and QoS.  Upon further investigation we've found that the default spanning tree settings on the 6248 are RSTP and on the 3548s it's STP.  My first question is could the spanning tree configuration differences between the switches be causing our connectivity/unison blinking issues? My second question is, if not does anyone have any thoughts on why the activity lights would be behaving this way outside of a broadcast storm?  I've used Wireshark to get a look at the packets from several different mirrored ports and the largest percentage of packets are ARP and ICMP.  - Thanks!

PCHTech · Accepted Answer

Thanks for the reply. We have since resolved the issue. It turned out that our primary switch wasn't set as the root bridge and port fast wasn't enabled on our non-switch connected ports. This was resulting in almost constant topology changes which caused the switches to act as hubs rather than switches.

bct365 · Answer

What mode are the switches in? Do you have loop guard or BPDU guard enabled? Is VoIP in use of these switches?

I would like to help answer this but, not knowing what is on these, I don't want to give you the wrong info and create a bigger mess.

If you can upload a sanitized config of the switches, that would be extremely helpful.

bct365 · Answer

What mode are the switches in? Do you have loop guard or BPDU guard enabled? Is VoIP in use of these switches?

I would like to help answer this but, not knowing what is on these, I don't want to give you the wrong info and create a bigger mess.

If you can upload a sanitized config of the switches, that would be extremely helpful.

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