check the following guide https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/layer2/configuration/guide/b_Cisco_Nexus_7000_Series_NX-OS_Layer_2_Switching_Configuration_Guide/config_stp.html    

I get the same problem after upgrading three ASA 5540s from 1GB to 2GB of RAM in order to load 8.3 code.None of the firewalls will boot.

Hello GurooA transparent firewall, unlike the default router mode, operates at layer 2 and connects the same network on the inside and outside interfaces.HTH

Also,A misconfigured Discovery scan on the Symantec System Center can cause a tremendous amount of traffic on this port. A high amount of traffic may indicate that the Symantec System Center Discovery service is configured to run frequent intense dis...