From: Chua, Parry (Parry.Chua@xxxxxxxxxx)
Date: Fri Mar 01 2002 - 21:59:32 GMT-3
This is coorrect, in fact it is the lowerest sum value =(priority + mac address
) that become the root. Disable STP can cause loop within the vlan and it is no
t desire. You should use
the priority value to control which are the switch(port) is more prefenece to b
ecome root.
As you know the default priority is set to the mid-value(32768).
-----Original Message-----
From: Przemyslaw Karwasiecki [mailto:karwas@ifxcorp.com]
Sent: Saturday, March 02, 2002 4:19 AM
To: Joseph Ezerski
Cc: 'alain faure'; 'Leigh Anne Chisholm'; 'Clark J';
ccielab@groupstudy.com
Subject: RE: a question on SPANTREE
Joseph,
This statement is taken vaebatim from CCO:
"The switch with the highest bridge priority (the lowest numerical
priority value) is elected as the root switch. If all switches are
configured with the default priority (32768), the switch with the
lowest MAC address in the Layer 2 network becomes the root switch"
Here:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_6_3/config/span
tree.htm#xtocid129753
(beware wrap)
According to this priority 0 will garantee that switch will
become root, because it is lowest numerical priority value.
I understand that I am missing something, as you sound
very confident in your statement, which is contradictory
to CCO. Can you please clarify a bit more?
Thank you,
Przemek
On Fri, 2002-03-01 at 14:47, Joseph Ezerski wrote:
> Alain, I am assuming that you only have one vlan? The command you entered
> here will set the spantree priority first to 0, then back to 65535 but only
> for VLAN 1.
>
> Try this instead:
>
> set spantree priority 0 <vlan #>
>
> Do that for every vlan you have but only on the root bridge. Leave every
> other switch the default. Note that you stand a good chance of seeing a
> major recovergence if you are entering that command on the switch that is
> not currently the root.
>
> That will work. I am 100% sure.
>
> Forget about root guard for now. Spantree Priority 0 protects you from
> about 99.999% of anything else becoming the root.
>
> -Joe
>
> -----Original Message-----
> From: alain faure [mailto:alainfaure@yahoo.fr]
> Sent: Friday, March 01, 2002 11:30 AM
> To: jezerski@broadcom.com; 'Leigh Anne Chisholm'; 'Clark J';
> ccielab@groupstudy.com
> Subject: RE: a question on SPANTREE
>
>
> hi,
>
> to solve the problem with another way i try :
> - set spantree priority 0
> - set spantree priority 65535
> - set spantree guard root 4/28 (one port of my catalyst)
>
> Without success, any comments ?
>
> Best regards
>
> --- Joseph Ezerski <jezerski@broadcom.com> a icrit : > If you want to get
> really advanced and you have bigger switches, like the
> > Cat6509, look into the root guard feature.
> >
> > -Joe
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > Leigh Anne Chisholm
> > Sent: Friday, March 01, 2002 10:34 AM
> > To: alain faure; Clark J; ccielab@groupstudy.com; clark.j@163.com
> > Subject: RE: a question on SPANTREE
> >
> >
> > That's a drastic response to what is actually a simple problem. In
> > implementing that solution, you're creating the potential for problems
> well
> > beyond those that you want to resolve. Spanning Tree has a simple
> priority
> > system that's easy to manipulate that doesn't have the implications of
> your
> > solution.
> >
> > Check the CCNA curriculum for information on how to configure a switch so
> > that
> > it can't become the root switch in any given VLAN.
> >
> >
> > -- Leigh Anne
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > alain faure
> > Sent: Friday, March 01, 2002 11:23 AM
> > To: Clark J; ccielab@groupstudy.com
> > Subject: Re: a question on SPANTREE
> >
> >
> > hi,
> >
> > that's interresting question, and we have a long debate on this with some
> of
> > my
> > friends about one of our customer site.
> >
> > for me, i think the better way (but they don't agree with me) is to
> disable
> > spanning tree on the VLAN for the switch you don't want they become root ?
> > What
> > do you think about ?
> >
> > best regards
> >
> >
> > --- Clark J <clark.j@163.com> a icrit : > Dear CCIEs and Near CCIEs,
> > > How to configure a switch so that it can't become the root switch in
> > VLAN
> > A
> > > ?
> > > Best regards,
> > > Clarke J
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