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RE: vlan minimization posted 11/14/2003
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The fact that the switch won't send any VLAN 1 user traffic on the link is enough to stop any loop.  The only traffic allowed out of the switch on VLAN 1 would be switch-originated: CDP, VTP, and the channel/trunk negotiation protocols.  As long as it's a Cisco switch on the other end, they won't be propagated beyond there, so there's no chance of looping.  An unmanaged switch might not understand CDP or VTP and may propagate it.  Same with other vendor's managed switches.  So I guess if you're going to use it, use it on every switch on your network.  If you're network is mixed vendor, I think you're off not using it though...

Chuck Church
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
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-----Original Message-----
From: Ozgur Guler (Garanti Teknoloji) [mailto:OzgurG@xxxxxxxxxxxxxx]
Sent: Friday, November 14, 2003 2:30 AM
To: 'Ccielab (E-mail)
Subject: vlan minimization

hello group,

cco says
"To reduce the risk of spanning-tree loops or storms, you can disable VLAN 1
on any individual VLAN trunk port by removing VLAN 1 from the allowed list.
This is known as VLAN 1 minimization. VLAN 1 minimization disables VLAN 1 (the
default VLAN on all Cisco switch trunk ports) on an individual VLAN trunk
link. As a result, no user traffic, including spanning-tree advertisements, is
sent or received on VLAN 1. "
isnt that statement somewhat contradictory by itself...
it says "To reduce the risk of spanning-tree loops or storms"
then it says no user traffic, including spanning-tree advertisements, is sent
or received on VLAN 1.
afaik, blocking spanning tree advertisement is "a reason" for spt loops.
i would be happy if someone can shed some light on this one.


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