Dear All
I have connected cable between two ports in the same switch on port FastEthernet0/14 and FastEthernet0/16, when I did show spanning tree block I found both ports are block and there was no any service impact, why the loop didn’t make down for the network, in below the configuration on the interfaces and core switch:
On Core:
spanning-tree mode rapid-pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
spanning-tree vlan 210 priority 0
!
Access switch
interface FastEthernet0/14
switchport access vlan 210
switchport mode access
switchport block multicast
switchport block unicast
switchport port-security maximum 3
switchport port-security
switchport port-security aging time 2
switchport port-security aging type inactivity
!
interface FastEthernet0/16
switchport access vlan 210
switchport mode access
switchport nonegotiate
switchport block multicast
switchport block unicast
switchport port-security maximum 3
switchport port-security
switchport port-security aging time 2
switchport port-security aging type inactivity
Thanks
