access and trunk on the same port ?

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Aug 7th, 2009
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Hi


Why do we have the command "switchport access vlan 401 " for this interface when it is trunking


interface GigabitEthernet0/47

description trunk downlink

switchport access vlan 401

switchport trunk allowed vlan 400-510

switchport mode trunk


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Edison Ortiz Fri, 08/07/2009 - 11:33
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If the port fails to trunk, it can use that command to associate itself to a Vlan.


At its current state, trunk up and running, the command won't be used. BTW, the native Vlan on the trunk would be Vlan 1 - make sure the directly connected device also uses Vlan 1 as the native Vlan.



HTH,


__


Edison.

CCDECCDE9 Fri, 08/07/2009 - 11:41
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you mean the switch that is trunking with this port uses vlan1 as native vlan ?Also what is the benefit of port putting itself into that VLAN when trunking is broken since other vlans cannot passthrough anyways ?

Edison Ortiz Fri, 08/07/2009 - 12:00
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you mean the switch that is trunking with this port uses vlan1 as native vlan ?


Yes, you can verify with the commands:


show interface fx/x switchport

or

show interface trunk


Also what is the benefit of port putting itself into that VLAN when trunking is broken since other vlans cannot passthrough anyways ?


I'm not sure what you mean about benefit. It's your typical Vlan membership configuration. Deciding what port each switchport belongs to in access mode is part of a design - not a benefit. Based on the configuration, Vlan 241 must have a special meaning on the switch and that's the Vlan to use of the port fails its trunk negotiation.


Other Vlans may not pass thru since the trunk is broken but it doesn't mean the interface is down/down state. If the interface is up/up, you can still communicate via Vlan 241.


HTH,


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Edison.

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