Natvie Vlan

acbenny · ‎11-21-2007

Hi all,

What is Native Vlan? what is Native Vlan mismatch ?

Edison Ortiz · ‎11-21-2007

A trunk port configured with IEEE 802.1Q tagging can receive both tagged and untagged traffic. By default, the switch forwards untagged traffic in the native VLAN configured for the port. The native VLAN is VLAN 1 by default.

A mismatch occurs when the link partners do not agree on the native vlan.

s.arunkumar · ‎11-21-2007

and to add a little more..

native vlan is used by protocols like Pgap,cdp,stp(bpdu),dtp etc.In isl trunking these signals are via vlan 1 which is by default the native vlan.In 802.1q only dtp is sent via native vlan as untagged and others are send via vlan 1 tagged(case:when native vlan is not vlan 1)..

:)

u346874_2 · ‎11-21-2007

Does that mean that if i have configure under trunk port command "switchport trunk native vlan 2" then 802.1q only dtp is sent via native vlan as untagged and others are send via vlan 1 tagged. If i want to clear the native VLAN from all 802.1Q trunks what is the command to do that (to set802.1Q all-tagged mode) Little amazed what is the basic configuration to set trunk port to all tagged mode and how to clear native vlan 1 from trunk port.

Thanks

Juha

Edison Ortiz · ‎11-21-2007

>If i want to clear the native VLAN from all 802.1Q trunks what is the command to do that (to set802.1Q all-tagged mode)

_______________

The command is vlan dot1q tag native

bvsnarayana03 · ‎11-21-2007

Refer this link which had a detailed discusion on this topic:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.2cbe4e88/4#selected_message

http://www.cisco.com/en/US/products/hw/switches/ps708/products_white_paper09186a008013159f.shtml

pls rate if helped.