Hello Feroz,
so far as my understanding goes ur absolutely right.
BPDUfilter when enabled on an interface just filters BPDUs in both directions, which effectively disables STP on the port.Bpdu filter will prevent inbound and outbound bpdu but will remove portfast state on a port if a bpdu is received.Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in spanning-tree loops.
when (spanning-tree portfast bpdu-filter default) enabled Globally , an STP port enabled with portfast is not assumed to recieve BPDUs, However, if for any reason the port recieves BPDUs, the Port shall go into (Blocking , listening , learning and then Forwarding state ) and the port will be subject to noramal STP calculations whether being in forwarding or blocking state.
