query on Port Fast and BPDU Filtering

Unanswered Question
Dec 5th, 2009

Dear All,

1) Port Fast Feature:

i read about port fast, it says that enable STP port fast on access port where PCs or servers are connected causes forwarding state immediately bypassing listening and learning state, but confusion is that how that port will become in forwarding state whereas PC is connected..

please clarify me ASAP..

2) BPDU Filtering Feature:

when i read about this feature in BCMSN book, it says that in first para that it prevents switches from sending BPDUs on portfast enabled interfaces, portfast enabled interfaces connected to PCs hence dont participate in STP and drops the reced BPDUs

and next immediate para says that if globally enabled, switch changes the interface back to normal STP operation if the port receves BPDU on the respective interface. if portfast enabled interface receives a BPDU, it immediately loses its portfast status with BPDU filtering enabled.

also its says : CAUTION::: config of BPDU filtering on a port connected to another switch may results in a bridging loop, use caution when deploying  BPDU filtering. BPDU filtering is not a recommended config

what all does this means all about?

please help me!

Thanks and Regards,


I have this problem too.
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