Re: STP, Uplink fast & Backbone fast

I think for the most part you understand what is going on here Sarad, but I
wanted to make a few comments for you

1) Backbonefast should be implemented on all switches in the topology
according to the documentation.
2) backbonefast and uplinkfast serve similar purposes, but not exactly the
same. Think of uplinkfast as providing an alternate upllink port to the
root bridge -- an alternate root port. Backbonefast on the other hand is
specifically for indirect link failures and provides a backup to the
designated port on a segment.

Also, check out the following doc, it is a good one.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800c2548.shtml#recovers

On Sun, Nov 15, 2009 at 7:11 PM, Sarad <tosara_at_gmail.com> wrote:

> Hi Group,
>
> Just trying to crack STP & it's features. I have some doubt on followings.
>
> I understand that backbone fast has a big query process compared to uplink
> fast. Just trying to relate those two & understand please correct me if I
> am
> incorrrect.
>
> 1. When we compare uplinkfast & backbonefast, Uplink fast will be
> configured
> on the access layer when there are two uplinks or switch is not in the
> transit path.
>
> 2. backbone fast will be implemented on the switches in the transit path
> which has multiple links & more prone to create loops.
>
> Those two methods are used to acheive the same purpose but Backbonefast
> process is more insentive as where it implements is more prons to create
> loops than places where we implement Uplinkfast
>
> The other thing I am trying to crack is,
>
> When we introduce a new switch to stable STP network what will happen in
> following schenarios.
>
> 1. New switch not become a root - In this case no user traffic will be
> affected in any of the vlan in any existing switches
>
> 2. New switch becoming a root for some existing VLANs - User traffic will
> be
> affected till STP topology stabilized.
>
> Please help me to verify my understanding & observations are correct.
>
> regards
> Sarad
>
>
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