From: Scott Morris (smorris@ipexpert.com)
Date: Wed Oct 03 2007 - 21:10:59 ART
I think we have a few different sets of thoughts going on here.
What does the "priority" parameter actually do for us? It modifies the
BRIDGE priority which will influence the root bridge selection for that
particular instance. While that may modify which direction things go, it
may not be the only thing we have to modify (look at "show spanning" to find
out!).
"Set the switch priority for the specified spanning-tree instance. This
setting affects the likelihood that the switch is selected as the root
switch. A lower value increases the probability that the switch is selected
as the root switch." -- DocCD
If you aren't interested in modifying which switch is the root bridge but
rather looking at a per-port idea of which direction things go, then the
spanning-tree cost or port-priority are things you can modify.
As a note, spanning-tree cost in a two-device viewpoint will affect local
decisions only. Port priority can be set on one switch to modify another
switches' behavior.
HTH,
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
A Cisco Learning Partner - We Accept Learning Credits!
smorris@ipexpert.com
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
slevin kremera
Sent: Wednesday, October 03, 2007 7:45 PM
To: Rich Collins
Cc: Cisco certification; Joseph Brunner; Brian Dennis
Subject: Re: mst priority
that was my second doubt too
joe /Brian ur thoughts
On 10/3/07, Rich Collins <nilsi2002@gmail.com> wrote:
>
> I would say your first choice is easier and cleaner if you are allowed
> to configure on both switches. I would use the second method if you
> are not allowed to touch one switch and have to then modify cost or
port-priority.
>
> Actually I have a question to the first method.
> It is preferable to set priority 0 or set to root?
>
> Rich
>
>
> On 9/29/07, slevin kremera <slevin.kremera@gmail.com> wrote:
> >
> > There is a mst configuration between sw1-sw2-sw3 and there are 2
> > instances.Also there is etherchannel pagp configured between these 3
> >
> > instance 1 13-14-15
> > instance 2 16-17-18..........
> >
> > i want instance 1 to take one etherchannel and instance 2 to take
> > other.Myconfusion is..shud i set spanning-tree mst 1 priorty 0 on
> > sw1 and instance 2 priority 0 on switch 2
> >
> > or
> >
> > go to etherchannel 1 in sw1 and set instance 1 with lower priority
> > goto etherchannel 2 in sw1 and set instance 2 with lower priority
> >
> > ____________________________________________________________________
> > ___ Subscription information may be found at:
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