Cisco Troubleshooting Commands for Input/Output Drops

Some common commands that can help troubleshoot packet discards or drops:

show interface x/x/x

show interface x/x/x stats

show interface x/x/x switching

show cef not-cef-switched

show ip cef switching statistics

show ip cef switching statistics features

show ip traffic

show buffers

and if you suspect an issue with CEF, you can use:

debug ip cef receive