[c-nsp] VTP Pruning point .

[Darryl Dunkin]

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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