Trunk or "tunnel" vlans through layer 3 interfaces

Unanswered Question
Jun 11th, 2010

Hi all,

I was just wondering if there are ways to trunk or "tunnel" vlans through layer 3 interfaces.  This would be useful in extending vlans to remote sites that are 1 or more layer 3 hops away.



I have this problem too.
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arudolph_emd Fri, 06/11/2010 - 14:17

You could look into something like MPLS or L2TPv3.  L2TPv3 is easier to configure, but lacks features such as traffic engineering and has more overhead than MPLS.  Both allow you to encapsulate layer 2 traffic (VLANs) over layer 3 (IP) interfaces.  Would you really want to extend the broadcast domains of those VLANs over your WAN links to remote sites though?  You will be adding the overhead of MPLS / L2TPv3 as well as the additional broadcast traffic that would normally be contained to you LAN.  This could have significant impact on you WAN links.




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