From: bobdu11@cox.net
Date: Thu Sep 26 2002 - 06:51:19 GMT-3
Alright, let's say there is one switch in the scenario, then how to you ensure that this switch does not become root ? You turn off spanning tree for that VLAN....
>
> From: elping <elpingu@acedsl.com>
> Date: 2002/09/25 Wed PM 10:55:54 EDT
> To: Balaji Siva <bsivasub@cisco.com>
> CC: Chris <clarson52@comcast.net>, "Voss, David" <dvoss@heidrick.com>,
> ccielab@groupstudy.com
> Subject: Re: Consensus
>
> good point
>
>
>
> Balaji Siva wrote:
>
> > inline
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > Chris
> > Sent: Wednesday, September 25, 2002 10:03 PM
> > To: Voss, David; ccielab@groupstudy.com
> > Subject: Re: Consensus
> >
> > What happens when the switch hosting the root guard command goes down, get's
> > turned off etc?
> >
> > ### obviously the switch in question would be isolated and becomes a root.
> > but then point of STP root in a isolated switch is meaningless. It becomes a
> > useless feature...
> >
> > The ONLY way to ensure a switch or vlan will NEVER become root is to disable
> > spanning-tree on that switch or vlan, or turn off the switch.
> >
> > ### this is just taking the word too literally..and impractical solution..i
> > guess may be that is what is needed for the lab.
> >
> > ALL spanning-tree decision are based on the concept of a root. If you are
> > running spanning-tree there is a root somewhere. You cannot guaruntee that
> > any particular switch will never become root when this is the case. You have
> > to turn it off.
> >
> > ### understood..but again this issue to taken too literally...
> >
> > ----- Original Message -----
> > From: "Voss, David" <dvoss@heidrick.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Wednesday, September 25, 2002 9:03 PM
> > Subject: RE: Consensus
> >
> > > So the consensus for the following (I'm adapting it a bit):
> > >
> > > Make sure that your switch "never" becomes root for vlan 20.
> > >
> > >
> > >
> > > root guard on the port hosting VLAN20 if you have 2 or more switches
> > sharing
> > > VLAN20
> > >
> > > and
> > >
> > > disable spanning tree for VLAN20 if you have 1 switch
> > >
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Balaji Siva [mailto:bsivasub@cisco.com]
> > > Sent: Wednesday, September 25, 2002 7:59 PM
> > > To: Nick Shah; Voss, David; ccielab@groupstudy.com
> > > Subject: RE: Consensus
> > >
> > >
> > > This makes more sense..though the config is actually made on the
> > > neighbouring switches !!!
> > >
> > > It is probably used on distribution/core to prevent small access switches
> > > from becoming root..
> > >
> > > B
> > >
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > > Nick Shah
> > > Sent: Wednesday, September 25, 2002 8:42 PM
> > > To: Voss, David; ccielab@groupstudy.com
> > > Subject: Re: Consensus
> > >
> > >
> > > Set spantree guard is the ONLY sure shot way.
> > >
> > > I am willing to bet my $$$ on this one.
> > >
> > > To raise the odds on the bet :)
> > >
> > >
> > http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_6_1/config/s
> > > pantree.htm#xtocid2856623
> > >
> > > rgds
> > > Nick
> > > ----- Original Message -----
> > > From: "Voss, David" <dvoss@heidrick.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Thursday, September 26, 2002 9:51 AM
> > > Subject: Consensus
> > >
> > >
> > > > I've been going through the threads on spanning tree and one thread that
> > > > never had a consensus was how to ensure a switch would "never" become
> > > root.
> > > > There is not a text I have found that addresses this. From what I can
> > > tell,
> > > > one option is to turn off spanning tree completely, the other to set
> > > > priority to 65535. Neither sounds appropriate to me.
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