From: CCIEin2006 (ciscocciein2006@gmail.com)
Date: Thu Dec 15 2005 - 14:12:54 GMT-3
The way I understand it is spanning tree has two timers, maxage and forward
delay.
Maxage is 20 seconds, forward delay is 15.
So it goes like this:
Blocking -> Listening: 20 seconds (Maxage)
Listening -> Learning: 15 seconds (Forward Delay)
Learning -> Forwarding: 15 seconds (Forward Delay)
Total: 50 seconds
Actually in the real world I have timed it to be closer to 30 seconds for
the entire process.
When you enable portfast it bypasses all of the above.
If you set the forward-time to 0 seconds I think you would still have to
wait for maxage to expire which is 20 seconds. Try it in the lab and tell us
how it works...
On 12/15/05, Victor Cappuccio <cvictor@protokolgroup.com> wrote:
>
> Hello Friends..
>
>
>
> I'm courios about this, in
>
>
http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12225sec/3550scg/s
> wstpopt.htm#wp1031116 say us that
>
> Port Fast immediately brings an interface configured as an access or trunk
> port from a blocking state to the forwarding state, bypassing the
> listening
> and learning states.
>
>
>
> In my interpretation (IMI), and because the output of the
>
>
>
> spanning-tree vlan 2 forward-time ?
>
> <4-30> number of seconds for the forward delay timer
>
>
>
> result that the algortim (IMI) set the forwarding delay to 0, is that
> Correct? Or it simply see that there is some king of turn on flag and the
> continues to the next operation = That is Listening - Learning -
> Forwarding
>
> I'm correct, or there is something more in the middle?
>
>
>
> Thanks
>
> Victor.
>
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