I had wierd (for me) behavior in my network yesterday. I connect sw2 (2950C) to sw1 (6000) and it generates STP blocking and broadcast storm to the network, whole network was down because of that. There was no hosts connected to sw2. Network is flat. There is just basic spanning-tree configuration on switches.
switchport access vlan 100
switchport mode access
switchport trunk native vlan 199
switchport mode trunk
no ip address
I know that another side was access port (sw1) and another side was trunk (sw2). So that is not acceptable configuration, but I'm keen to now why it generates broadcast storm and that kind of BPDU messages.
I attach file, where is log from sw2. I don't have log from sw1.
Thanks in Advance,