Option #1 assuming the question means it will wait 16 seconds AFTER max_age
has already expired.  After max_age expires it is 2x forward-delay.

Option #2 assuming the question means it will wait 16 seconds in total.

I suppose it depends on how you interpret "...when a port fails".  My best
guess is option #1, but in the real lab if I got this,I would ask the
proctor and give him the information you just gave me so he knows that you
know what you are talking about.

Also:

Max-Age is still 20 seconds even with RSTP/MST (verify this by doing show
span in either of those modes).  There is a subtle difference.  RSTP/MST can
detect a failure in 6 seconds (3x hello-time of 2 seconds) but that is a
different function than the max age.  The hello BPDUs in RSTP/MST work
differently than in traditional STP and PVSTP+ because in RSTP/MST the
hellos are used between routers on each segment as sort of a "keepalive."

On Wed, Jul 22, 2009 at 9:08 PM, M Jay <[email protected]> wrote:

>  Hi
> I need help in this question:
>
> SW1 connected with SW2 through trunk ports, when a port fails the other
> port will wait for 16 second before the interface begins forwarding.
>
> Possible soltuions:
>
> SW1
> spanning-tree VLANx forward-time 8
>
> Or
>
> Spannin-tree VLANx forward-time 5
> spanning-tree VLANx max-age 6
>
> As forward-time includes listening and learning phases (5+5= 10) do I need
> to include the max-age time of 6 seconds ? Does max-age time effects in
> forwarding state of interface ??
>
> Please assist!!!!
>
> Thanks
>
>
>
>
>
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-- 
Regards,

Joe Astorino - CCIE #24347 R&S
Technical Instructor - IPexpert, Inc.
Cell: +1.586.212.6107
Fax: +1.810.454.0130
Mailto:  [email protected]
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