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New Member

802.1q on Catalyst : what about 'native VLAN port' and 'access port '?

Hi,

I don't see clearly the distinction between :

Access Mode VLAN: 2 (VLAN0002)

and

Trunking Native Mode VLAN : 5

Is Access Mode VLAN used in case of trunked port ?

what is interaction with native 802.1q Vlan port ?

Thanks

Luc Mignerey

Switch#sh interfaces fastEthernet 0/6 switchport

Name: Fa0/6

Switchport: Enabled

Administrative mode: static access

Operational Mode: static access

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: Disabled

Access Mode VLAN: 2 (VLAN0002)

Trunking Native Mode VLAN: 5 ((Inactive))

Trunking VLANs Enabled: NONE

Pruning VLANs Enabled: NONE

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: 802.1q on Catalyst : what about 'native VLAN port' and 'acce

There is not a connection between the two. I agree that having the switchport provide information on trunking when it is an access port is confusing.

The native vlan is the vlan that will move across the trunk port untagged.

In otherwords, if the recieving port gets a frame sent to it without a dot1q tag in it, it will tag it with the native vlan's ID.

In this case, this is a access port and the information provided by "Trunking Native Mode VLAN: 5 ((Inactive))" can be ignored entirely.

It is also important to note if the port is dynamically trunking and trunking will not come up, it will be a access port with the native vlan has its vlan id.

4 REPLIES
Cisco Employee

Re: 802.1q on Catalyst : what about 'native VLAN port' and 'acce

There is not a connection between the two. I agree that having the switchport provide information on trunking when it is an access port is confusing.

The native vlan is the vlan that will move across the trunk port untagged.

In otherwords, if the recieving port gets a frame sent to it without a dot1q tag in it, it will tag it with the native vlan's ID.

In this case, this is a access port and the information provided by "Trunking Native Mode VLAN: 5 ((Inactive))" can be ignored entirely.

It is also important to note if the port is dynamically trunking and trunking will not come up, it will be a access port with the native vlan has its vlan id.

New Member

Re: 802.1q on Catalyst : what about 'native VLAN port' and 'acce

Thnaks for your help

Luc Mignerey

New Member

Re: 802.1q on Catalyst : what about 'native VLAN port' and 'acce

Hi,

It's no so clear for me. Am I right with:

- when the port is trunking the "Access Mode VLAN" could be ignore, and no tagged frame are associated with the "Native VLAN"

- when the port is NOT trunking (i.e. in Access Mode), the port is associated with the "Access Mode VLAN" ID, and the "Native VLAN" has no significance ?

Thanks for this clarification.

Regards

Francois Buntschu

Re: 802.1q on Catalyst : what about 'native VLAN port' and 'acce

Exactly so.

Kevin Dorrell

Luxembourg

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