×

Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.
Julio Carvajal Sat, 05/03/2014 - 18:57
User Badges:
  • Purple, 4500 points or more

Hello,

 

Not sure what you mean but remember that tags only flow over Trunk links,

 

Now if you want a specific subnet/vlan to be untagged then just make sure it's the native VLAN.

 

Makes sense?

 

Regards,

 

medbarki1 Sun, 05/04/2014 - 02:06
User Badges:

hello 

 

ok thank you julio,

 

but can you explain with an example of configurations

 

regards.

InayathUlla Sharieff Sat, 09/13/2014 - 06:54
User Badges:
  • Cisco Employee,

Hi,

I am not going to you use your diagram just explaining here:

Below explanation in layman term:

1)

Access Port---Means untagged port. 

Int f0/1

Switchport mode access

Switchport access vlan 10 >> Which means the port is part of vlan 10 and its in untagged state.

 

Trunk Port--Means Tagged Port:

Int G0/1

Switchport mode trunk

Switchport trunk allowed vlan 10 >>> Which means that if the trunk is up and working fine the packet going out of this interface would have tag on it with vlan 10. Trunk port - frames will be sent with VLAN tag. If only one VLAN allowed, then only frames with allowed vlan tag will be sent

 

Switchport trunk allowed native vlan 20  >>> Which means that the packet though it is passing through the trunk port but still it would not be tagged.

 

2)

Another way of explaining this would be:

A trunk allows pretagged packets to passthrough without changing the tag while an access port takes the packets it receives and retags them.

 

Ex.  To setup a trunk to allows all vlans(pretagged) traffic to flow to and from it

 

int fa0/0

switchport mode trunk <------ explicitly making this port a trunk rather than allowing it to "negotiate" its role (only command needed)

 

Ex.  To setup an access port and telling to tag the traffic as vlan 10

 

int f0/1

switchport mode access <----- explicitly making this an access port rather than allowing it to "negotiate" its role

switchport access vlan 10  <--------- tell this interface to tag any traffic entering the port as vlan 10

 

HTH

Actions

This Discussion