[c-nsp] VLAN tagging on the 2960

[Enno Rey]

Hi,


On Thu, Feb 07, 2008 at 11:20:52AM -0600, Kiecker, Alan W wrote:
> I need to set up ports on a 2960-24TC-L so that outbound ports retain
> the VLAN tag.
> 
> I have configured the ports as trunks with VLAN IDs 7 and 13.  The
> native VLAN is 13.  This should tag any inbound untagged packets with
> VLAN 13.

no. as far as I remember "native vlan" means: when a packet arrives on a port belonging to this vlan, do _not_ tag it when sending it over a trunk. "native vlan" kind-of means: "play that 802.1q does not exist" ;-)





  This is what I want, but outbound packets are a different
> story.
> 
> The command reference states in the Usage Guidelines for the "switchport
> trunk" command that "If a packet has a VLAN ID that is the same as the
> sending-port native VLAN ID, the packet is sent without a tag;
> otherwise, the switch sends the packet with a tag."  
> 
> My interpretation of this is that outbound packets with VLAN ID 7 will
> be sent with the tag, but packets with VLAN ID 13 will be sent without
> the tag.
> 
> Is there anyway to not have this tag removed?

yes... just use another vlan as the native one (and, in your case, do not use vlan 7. use - say - vlan 666).
and: "removed" is a bit misleading (term) here. packets arriving at ports (usually) have no tags at all (why should they, anyway?). They get tagged when sent over a trunk (to inform the other end: "this packet belongs to vlan xy"). So (usually) there's nothing to be "removed". just something (= the tag) to be added. in all cases except for the "native vlan"...

thanks,

Enno


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