From: Phil (ccie9323@yahoo.com)
Date: Fri May 28 2004 - 10:07:34 GMT-3
Carlos,
You are correct, first comes the cost to the root and
then the bridge ID as a tie breaker.
Thanks,
Phil
--- Carlos G Mendioroz <tron@huapi.ba.ar> wrote:
> You are missing the first check, which is path cost.
> Only when comparing even path costs comes the
> sending switch ID
> comparison...
>
> Phil wrote:
>
> > I agree, there is only one root bridge, but the
> STP
> > path is built by first, checking the bridge
> > priorities, then the port priorities and last, the
> > port cost.
> >
> > You can manipulate the bridge priorities in you
> domain
> > as you please to build the STP path you want.
> >
> > By default all bridge priorities are 32768,
> issuing
> > the command spanning-tree root primary lowers the
> > priority to 8192 and spanning-tree root secondary
> > lowers the priority to 16384. Because the other
> two
> > switches still have a priority of 32768 the link
> > between them will be blocked.
> >
> > Phil
> >
> > --- Carlos G Mendioroz <tron@huapi.ba.ar> wrote:
> >
> >>I don't think so.
> >>There's only one root bridge in a converged STP
> >>domain.
> >>Changing a non-root bridge priority will have no
> >>impact in the STP
> >>topology...
> >>
> >>
> >>Phil wrote:
> >>
> >>
> >>>Tom,
> >>>
> >>>You have to make cat2950#1 the secondary root to
> >>>acomplish this. First, STP checks the bridge
> >>
> >>priority
> >>
> >>>and then the port cost as a tie breaker.
> >>>
> >>>Phil
> >>>
> >>>--- Tom Young <gitsyoung@yahoo.co.jp> wrote:
> >>>
> >>>
> >>>>Hi, group
> >>>>
> >>>> I confused on the spantree question. I
> >>
> >>connected
> >>
> >>>>the
> >>>>network as below, two cat6509s and two cat2950s,
> >>
> >>the
> >>
> >>>>cat6509#1 for the STP root and the cat6509#2 for
> >>
> >>the
> >>
> >>>>secondary root. The port that connect cat2950#1
> >>
> >>from
> >>
> >>>>cat2950#2 was blocked by STP function. I want to
> >>>>block the
> >>>>port that from Cat6509#2 to Cat2950#2. I tried
> the
> >>>>next
> >>>>two commands, but failured, how can I do ? Help
> >>>>me,please.
> >>>>
> >>>>set spantree portvlancost 3/3 cost 200
> >>>>set spantree portcost 3/3 cost 200
> >>>>(the port 3/3 of cat6509#2 was connected with
> >>>>cat2950#2)
> >>>>
> >>>> cat6509#1------cat6509#2
> >>>> | |
> >>>> | |
> >>>> cat2950#1------cat2950#2
> >>>>
>
>>>>__________________________________________________
> >>>>Do You Yahoo!?
> >>>>http://bb.yahoo.co.jp/
> >>>>
> >>>>
> >>>
> >>>
> >
>
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