Does portfast disable Spanning-Tree?

This topic is to discuss the following lesson:

Hi Rene,

I realized when you show
SW1#show spanning-tree interface FastEthernet 0/24 detail

q1) The “bpdu receive” is 0 - why ? ( non-root bridges do not send bpdu to root bridge ?)

q2) What is the difference between “P2P Edge” and “P2P” ? What do that actually meant ?

q3) Do we use portfast on ports that we are sure will not cause a loop ?


Hi Alan,

  1. With PVST, BPDUs are relayed from the root bridges down the tree to other non-root bridges.
  2. P2P Edge means that portfast has been enabled. Portfast enabled interfaces don't trigger a TCN. Take a look at the portfast tutorial here, I explained it there.
  3. That's right, Cisco IOS warns you when you enable it on interfaces. It doesn't disable STP though so it's not like you will have permanent loops.