From: Nate Cielieska (ncielieska@gmail.com)
Date: Wed Jul 16 2008 - 23:51:45 ART
Chris,
Based on the fact that a failure constituted the STP topology change.. and
we are talking about Classical STP (as opposed to RSTP) i would say that
your maxage comes into play here. Based on failure the way i understand it
is that STP needs to do a sanity check to make sure that the port going down
is validly going down and adjust its topology accordingly, afterwhich your
forward delay kicks in.
Contrast to that if you plugged a new port into a switch, there is nothing
to age out.. so forward-delay x2 and then forwarding would take precedence.
I would be interested to hear on the theory of other master blasters but the
quick way i think about it is:
Existing port into a failure condition -> Maxage applies
New port coming into the envionrment -> No Maxage countdown.
Regards,
Nate
On Wed, Jul 16, 2008 at 5:26 PM, cciestudy <cciestudy@mid-world.net> wrote:
> I would read the question to cover only how long it takes for a specific
> port to go from blocking to forwarding, which would be the listening and
> learning timers. (2x4sec = 8sec). So, I would set the forward STP timer on
> the root bridge to 4 sec.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Christopher Copley
> Sent: Wednesday, July 16, 2008 2:34 PM
> To: ccielab@groupstudy.com
> Subject: Basic STP question
>
> All,
>
> This is one of those basic questions that you dont think about until you
> have to do it but I am unclear of a requirement and would like everyones
> thoughts. STP convergence, I have a question that reads as follows...
>
> Configure your Layer 2 network to forward packets in 8 seconds after a
> failure.
>
> My thinking is I would set the Hello time to 1sec and the forward time to 4
> seconds and leave max age alone. Is this correct? and also should I modify
> the hello time at all? I set this up in my home lab and it appears to
> work, but does it meet the requirements of the question?
>
>
> Thanks,
> Chris
>
>
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