From: Scott Morris (swm@emanon.com)
Date: Wed Aug 30 2006 - 13:33:31 ART
While technically your thinking is correct and a good idea in REAL LIFE
network design, in the CCIE lab you are often presented with scenarios that
logically would not play in real life.
Don't over-think things! With a two-switch ethernet network, there really
isn't any magical difference that setting the max-age timer is going to
play! Watch your "show spanning-tree" information to see what the switches
do.
Although the lab scenario may ask you to specifically change one piece,
don't automatically assume you have to recalculate everything else! If you
aren't asked to, don't do it.
If the scenario asked you to keep all of the 802.1D ratios, yet still make
convergence time faster with those specifics, THEN perhaps you'll think down
this path!
Believe me, this is a path that many people take because of real-world
expectations that we have and knowledge of the actual
application/implication of changing things like this. But in a lab
environment, particularly with the limited pieces of equipment that we have,
you should ask yourself whether it will make a difference, or not work
properly otherwise.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPExpert VP - Curriculum Development
IPExpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Sean
C
Sent: Wednesday, August 30, 2006 11:49 AM
To: ROCHA Leandro ORANGE-FT; Aamir Aziz
Cc: GroupStudy
Subject: Re: Forward-delay time
Hi Leandro,
If the task was asking to go from blocking to forwarding state in under 16
secs, wouldn't that be when you would take into consideration the max-age
timer?
This task specifically states to alter the forward-delay time only, nothing
about altering the entire STP equation - "Configure the forward-delay time
of a Vlan X under 16 seconds." Taking the task into consideration, I would
just alter the forward-time to a value of 7.
I understand what you're trying to do, I'm just not sure that your answer
would meet the requirements of this task.
Also, Aamir - to answer the 2nd part of your original post - "do we need to
issue this command on both the switches or only on where the Vlan X exists."
- while, technically, you would only need to apply it to a switch where the
vlan exists - personally - as long as the vlan in question is able to be on
the 2nd switch (no vlan pruning, or the switch w/out the vlan is a VTP
transparent switch, etc...), I would apply the timer to both switches.
Or, if I was really questioning it, I would ask the proctor something along
the lines of "Should I take into consideration the chances of that vlan
being used on the 2nd switch in the future?...."
HTH,
Sean
----- Original Message -----
From: "ROCHA Leandro ORANGE-FT" <leandro.rocha@orange-ft.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, August 30, 2006 10:05 AM
Subject: RE: Forward-delay time
> I think we have to take in account the max-age timer too.
>
> To have less than 16 seconds in any case, we should put max-age to 6 and
> fwd-delay to 4 (the minimum values).
>
> Then we have a total of 6+4+4=14.
>
> Leandro
>
>
>
>
>
> "Brian McGahan" <bmcgahan@internetworkexpert.com>
> Sent by: nobody@groupstudy.com
> 08/30/06 10:39 AM
> Please respond to "Brian McGahan"
>
>
> To: "Aamir Aziz" <aamiraz77@gmail.com>,
<ccielab@groupstudy.com>
> cc:
> bcc:
> Subject: RE: Forward-delay time
>
>
>
> The forward-delay command configures each of the listening and
> learning phase timers. This means that if you have it configured as 15
> that it will take 30 seconds to go through both phases. If you want to
> move from blocking to forwarding in less than 16 seconds your forward
> delay would have to be 8 or lower.
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
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>
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Aamir Aziz
> > Sent: Wednesday, August 30, 2006 6:48 AM
> > To: ccielab@groupstudy.com
> > Subject: Forward-delay time
> >
> > Hi there,
> >
> > If the task says Configure the forward-delay time of a Vlan X under 16
> > second then what value do we use 15 or 16?
> >
> > #spanning-tree VLAN X forward-time 15 or 16
> >
> > since by default it is 15, and do we need to issue this command on
> both
> > the
> > switches or only on where the Vlan X exists.
> >
> > Thanks
> > Aamir
> >
> >
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