stp port states

Unanswered Question
Jul 14th, 2008

hi everybody !

i just want to know if port in forward state stops receiving bpdu , will it transition to blocked state asuming all the stp timers have expired ?

thanks a lot and have a wonderful day !

I have this problem too.
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dhananjoy chowdhury Mon, 07/14/2008 - 17:55


In forwarding state, it will Send and receive BPDUs, learn MAC addresses, and send and receive data, as long as port is up and loop is not detected.

Hope this helps.

sarahr202 Mon, 07/14/2008 - 18:46

thanks for your reply, however it did not address my question. I know a port in forwarding state does all of that you mentioned but the point is if the port in forward state does not receive any bpdu for over 50 seconds, what state would it transition to ?

thanks a lot !

Francois Tallet Mon, 07/14/2008 - 20:19


The port in forwarding state can be:

- designated port, in which case it does not expect any BDPU (cf your previous concern about max-age)

- root port, in which case it expect BPDUs from the designated bridge. If it fails to receive these BDPUs for max-age (20 seconds), it will move its *role* to designated. But it will stay forwarding. As it is not designated, we're back to the previous case where the port does not expect any BPDU...

Hope this clarifies!




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