Thanks Andrew. I have one more question, What is the real use of BPDU filter command in a Global mode, if a normal portfast can achieve the same functionality. Why do we need to enable BPDU filter at the global level and what enhancement does it provide at the global level. BPDU filter lesson says.
BPDUfilter can be configured globally or on the interface level and there’s a difference:
Global: if you enable BPDUfilter globally then any interface with portfast enabled will not send or receive any BPDUs. When you receive a BPDU on a portfast enabled interface then it will lose its portfast status, disables BPDU filtering and acts as a normal interface.