[c-nsp] VTP Pruning point .

[Ibrahim Abo Zaid]

Dear All

thanks for your replies , as i get VTP Subset advertisement messages handles
which VLANs are active on each switch

best regards
-- Abo Zaid

On Dec 5, 2007 4:59 PM, Murphy, William <William.Murphy at uth.tmc.edu> wrote:

> Pruning is handled by VTP messages...  When there are no active ports in a
> particular VLAN VTP tells the upstream switch to stop flooding traffic on
> that link.  Spanning tree is still functional for all the VLANs but
> uncessary traffic is pruned back...
>
> ________________________________
>
> From: cisco-nsp-bounces at puck.nether.net on behalf of Ibrahim Abo Zaid
> Sent: Wed 12/5/2007 2:27 AM
> To: Darryl Dunkin
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] VTP Pruning point .
>
>
>
> Dear Darry
>
> so prunuing is applied to traffic-forwarding only and all switches knows
> all
> the domain VLAN but the traffic is forwarded for the active VLANs only .
>
> so if VTP updates advertises all domain VLANs how the switches knows which
> VLAN is active and which aren't ? via STP BPDUs for PVSTP mode or how ?
> best regards
> ~Ibrahim
>
>
> On Dec 5, 2007 5:27 AM, Darryl Dunkin <ddunkin at netos.net> wrote:
>
> > Pruning is not to prune the configuration, but to prune the forwarding
> > of traffic between switch ports (VLANs forwarded on the trunk itself)
> > when that VLAN is not active on the neighboring switch. Even if the
> > traffic is pruned, the switches will still know about all VLANs in the
> > domain but not receive traffic for pruned VLANs.
> >
> > An example 'show trunk' on CatOS appears like this when VLANs are pruned
> > (2-5 are pruned on port 2/50 in this case).
> >
> > Port      Vlans allowed and active in management domain
> > --------
> > ---------------------------------------------------------------------
> >  2/50     1-9
> >
> > Port      Vlans in spanning tree forwarding state and not pruned
> > --------
> > ---------------------------------------------------------------------
> >  2/50     1,6-9
> >
> > The configurations are synced via VTP however and both switches know
> > about all 9 VLANs.
> >
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net
> > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Ibrahim Abo Zaid
> > Sent: Tuesday, December 04, 2007 18:22
> > To: cisco-nsp at puck.nether.net
> > Subject: [c-nsp] VTP Pruning point .
> >
> > Dears
> >
> > i have a question about VTP Pruning which is used to optimize broadcast
> > forwarding over trunk links in switched networks
> >
> > i think before doing so the switches needs to synchronizes VLAN
> > configurations between each other so i think VTP update
> > messages shall contain ACTIVE VLANs (VLANs which have active ports @ the
> > switch) instead of ALL-DEFINED VLANs
> >
> > and that truns Trunks from ALL-VLANs members state to ACTIVE-VLAN state
> > means it would be members of Active VLANs only not All domain VLANs
> >
> > i couldn't find any article verifies that point so if any one has an
> > idea is
> > that true or something else is used i will be appreciated for any help
> > :)
> >
> > best regards
> > --Abo Zaid
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> >
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