RE: excluding the native vlan from the trunk link

From: Rajat Chauhan (rachauha@cisco.com)
Date: Tue May 20 2008 - 04:58:23 ART


Hi Amin,

Control protocols always use native vlan or VLAN1, even if you clear it from
trunks.

CDP, VTP, and PAgP updates are always forwarded on trunks with a VLAN 1 tag.
This is the case even if VLAN 1 has been cleared from the trunks and is not
the native VLAN. If you clear VLAN 1 for user data, the action has no impact
on control plane traffic that is still sent with the use of VLAN 1.

http://www.cisco.com/en/US/products/hw/switches/ps700/products_white_paper09
186a00801b49a4.shtml#pre6

HTH.

Regards

Rachauha
CCIE R&S # 19814

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of ccie
Sent: Monday, May 19, 2008 3:43 PM
To: 'Cisco certification'
Subject: excluding the native vlan from the trunk link

Dear Exerpts,

 

Can I exclude the native vlan with such configurations?

 

interface FastEthernet0/23

 switchport trunk encapsulation isl

 switchport trunk allowed vlan 11,13,15

 switchport mode trunk

 switchport nonegotiate

 

If yes, how would the CDP and VTP messages be exchanges, once VLAN 1 has
been excluding over the trunk link?

 

Regards,

Amin



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