From: Menga, Justin (Justin.Menga@xxxxxxxxxx)
Date: Tue Dec 11 2001 - 19:07:43 GMT-3
Mas
Remember the root bridge calculation is performed on the ENTIRE bridge
id (priority + MAC address ID). Because priority is in the high order
bits, the value of the priority affects the calculation ahead of the MAC
address ID. Thus 0 could never be used for a special case...
Regards,
Justin
-----Original Message-----
From: Rodgers Moore [mailto:rodgers@the-moores.org]
Sent: Wednesday, 12 December 2001 10:39 a.m.
To: Mas Kato
Cc: ccielab@groupstudy.com; jianxin.liu@invisix.com
Subject: Re: Root Bridge
Engaged mouth before brain... I wish I still had some of my old docs,
somebody does do it this way... Of course there was Micom that ignored
the priority all together.
Rodgers Moore
Mas Kato wrote:
> <The only problem with 0 is this means that it cannot be the root
> bridge or considered in choosing a root bridge>
>
> Interesting. In every implementation I've dealt with, a bridge with a
> priority of zero indeed becomes the root bridge and only another
> bridge with a priority of zero and a lower bridge ID (MAC) can become
> root over it. I've recently verified this with CatOS and HP ProCurve.
>
> The Cisco discussion of the "Root Guard" feature explicitly mentions
> the zero value and its effect, at least on CatOS:
> http://www.cisco.com/warp/customer/473/74.html.
>
> Since the 802.1D standard isn't explicit about zero (just "lower"
> numbers mean higher root priority), I'd be interested to know what
> implementations take priority zero as a special case so I can file it
> away as a 'caveat.'
>
> Regards,
>
> Mas Kato
> https://ecardfile.com/id/mkato
>
> >Date: Mon, 10 Dec 2001 22:53:02 -0500
> > Rodgers Moore <rodgers@the-moores.org>Reply-To:
> >rodgers@the-moores.org Liu Jianxin-qch1927 <Jianxin.Liu@invisix.com>
> >Re: Root Bridge The only problem with 0 is this means that it cannot
> >be the root bridge or considered in choosing a root bridge. 1 is the
> >lowest value and highest priority for a device to be root.
> >
> >Rodgers Moore, CCIE# 8153
> >
> >Liu Jianxin-qch1927 wrote:
> >
> >> Yesterday somebody mentioned the 1 is the lowest value.
> >>
> >> But I check the CD, the range is from 0 to 65535.
> >>
> >> set spantree priority 0 should be the right answer.
> >>
> >> -----Original Message-----
> >> From: Albert Lu [mailto:albert_ccie@yahoo.com]
> >> Sent: Sunday, December 09, 2001 6:46 PM
> >> To: 'Mas Kato'
> >> Cc: ccielab@groupstudy.com
> >> Subject: RE: Root Bridge
> >>
> >> So what does setting the port priority to 8192 do? Isn't that the
> >> magic number?
> >>
> >> -----Original Message-----
> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf
> >> Of Mas Kato
> >> Sent: Sunday, December 09, 2001 7:11 PM
> >> To: ccielab@groupstudy.com; c_ccie@hotmail.com
> >> Subject: RE: Root Bridge
> >>
> >> [demime could not interpret encoding binary - treating as plain
> >> text] To assure it, use the 'set spantree priority 0' command.
> >>
> >> Regards,
> >>
> >> Mas Kato
> >> https://ecardfile.com.id/mkato
> >>
> >> > "CCIE Cisco" <c_ccie@hotmail.com> ccielab@groupstudy.com Root
> >> > BridgeDate:
> >> Sat, 08 Dec 2001 22:00:48 -0500
> >> >Reply-To: "CCIE Cisco" <c_ccie@hotmail.com>
> >> >
> >> >Hi,
> >> >
> >> >what is the command to make Catalyst5000 as root bridge without
> >> >using spantree root command.
> >> >
> >> >Thanks
> >> >
> >> >
> >> >
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