From: Cielieska Nathan (ncielieska@gmail.com)
Date: Wed Dec 12 2007 - 18:41:23 ART
I know i'm overthinking this.. apologies
But isn't rootguard configured on an interface? And it would have to
be applied on a downstream/Upstream switch to prevent that root from
going into root port state (on canidate switch) so to speak. This
isn't a configuration you could put on the root bridge to prevent any
other switch from becoming the root. The question below specifies
that the command would need to be entered on SW1..
Regards,
Nate
On Dec 12, 2007, at 4:22 PM, George Tosh wrote:
> How about using root guard to ensure that no other switches added
> to the
> topology may become the new root switch?
>
> http://www.cisco.com/warp/public/473/74.html
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of
> Cielieska Nathan
> Sent: Wednesday, December 12, 2007 2:43 PM
> To: George Goglidze
> Cc: Felix Nkansah; groupstudy
> Subject: Re: Permanent Spanning-tree Root Switch Question
>
> George,
>
> That is interesting. Thanks for the feedback.. if that is the case
> then i would be a little concerned with the question:
>
>> *SW1 should be set such that it would remain the root if even
>> other switches are added to the network in future
>
> The setting of 4096 wouldn't guarantee that... (another vendor
> switch, etc.)
>
> Is there something i'm missing from a command perspective? Is there
> something dynamic that will react to a spanning-tree priority coming
> in lower than its own?
>
> Nate
>
>
> On Dec 12, 2007, at 3:11 PM, George Goglidze wrote:
>
>> Hi Nathan,
>>
>> It does not actually react dynamically when the new router is added.
>>
>> the "spanning-tree vlan 20,30,40 root primary " is just a script
>> which will check current root switch's priority, and set 4096 less.
>> as well it calculates hello-interval and forward-interval if I'm
>> not mistaken, if you specify your network's size.
>>
>> but once the script is run, and later if you add another switch
>> with better priority,
>> it does not mean you will have your router re-calculate the
>> priority again.
>>
>> And as to the initial question, I'd just put 4096 as priority and
>> that's it.
>> also maybe I would ask proctor if new switches are going to have
>> default configuration of spanning tree or not.
>>
>> Regards,
>>
>>
>> On Dec 12, 2007 8:22 PM, Cielieska Nathan <ncielieska@gmail.com>
>> wrote:
>> Felix
>>
>> Do a spanning-tree vlan 20,30,40 root primary.
>>
>> The reason i would do that is because there are other calculations
>> besides priority that can come into play. Setting the root command
>> will allow the switch to react dynamically to spanning-tree elections
>> by tuning things in its favor to become root.
>>
>> Regards,
>> Nate
>>
>> On Dec 12, 2007, at 12:07 PM, Felix Nkansah wrote:
>>
>>> Hi,
>>>
>>> I am considering a spanning-tree task (dont have the answers tho).
>>>
>>> *It requires that, of the four switches in the network, SW1 be set
>>> as the
>>> root for VLANs 20, 30, 40.*
>>> **
>>> *SW1 should be set such that it would remain the root if even other
>>> switches
>>> are added to the network in future.*
>>>
>>> Would setting a command like *'spanning-tree vlan 20,30,40 priority
>>> 0'* be a
>>> good solution?
>>>
>>> I'm afraid the *'spanning-tree vlan 20,30,40 root primary'* command
>>> may not
>>> be able to cater for the 'future switches' caveat.
>>>
>>> Let me have your expert opinions, please.
>>>
>>> Regards,
>>>
>>> Felix
>>>
>>>
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