From: Scott Morris (smorris@ipexpert.com)
Date: Wed Sep 19 2007 - 15:33:57 ART
Well, you CAN make the changes any place you want, but like you said they
won't have any effect. ;)
You'll end up looking in "show spanning-tree" and see multiple timers where
one is configured, the other is running.
Root bridge is in charge.
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
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smorris@ipexpert.com
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Joseph Brunner
Sent: Wednesday, September 19, 2007 9:42 AM
To: 'alexey'; 'davidytk'
Cc: ccielab@groupstudy.com
Subject: RE: STP and Routing questions
Any and all changes must be made on the root bridge ONLY. The changes will
have no effect when made from a leaf switch!
If you want to "fake portfast" by changing the fwd delay timers to their
minimums, etc. you don't need to touch max age.
If you want to "fake uplinkfast", or run "uplinkfast" for only a vlan or 2
(uplinkfast is for ALL VLANS), then you tweak max age and fwd delay. Other
wise there is NO reason to touch max age.
You don't need to touch max age to influence how fast a port not receiving a
bpdu (i.e. host port) will hold a bpdu.
Would anyone like to see the debugs from my lab?
(or do your own, debug spanning-tree events)
LOL
-Joe
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
alexey
Sent: Wednesday, September 19, 2007 7:56 AM
To: davidytk
Cc: ccielab@groupstudy.com
Subject: Re: STP and Routing questions
2007/9/19, davidytk <davidytk@netvigator.com>:
>
> Default the STP port from blocking to fowarding is 50s.
Don't agree!
http://cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800949
54.shtml
"...The movement of a port into the listening state indicates that there is
a change in the active STP topology and that a port will go from blocking to
forwarding."
For a definition of these changes is Max Age. But two timer Forward Delay
responsible for the transition from BLK to FWD!
This timer is
> related to forward delay and max age
>
> 50s = 2*forward delay + max age.
>
> Default forward delay = 15s
> Default max age = 20s
>
> I think the question is related to this item. But there is some other
> ways to minimum the timer.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of alexey
> Sent: Wednesday, September 19, 2007 5:53 PM
> To: ccielab@groupstudy.com
> Subject: Fwd: STP and Routing questions
>
> > 1. What about max age time? The minimum max age is 6 seconds.
> > Minimum forward delay is 4 seconds.
> >
> > So 6+(4*2) = 14 seconds is the minimum, isn't it?
> >
> > Someone please verify these numbers...
>
>
> This is not true. Because the question specifically about port startup
> (BLK
> -> FWD), rather than on the time of convergence network (Max Age +
> -> Forward
> Delay + Forward Delay).
>
>
> > On 9/17/07, hadek.el-ayachi@nsn.com <hadek.el-ayachi@nsn.com> wrote:
> > > Hi Experts,
> > > I have the following questions:
> > > 1- In a non root switch, make the startup time of ports in vlan 15
> > > equal to 12 seconds?
>
>
> All changes timers should be done only at the root switch. Changes
> timers at non-root switches will not lead to any results. Am I right?
>
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