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fwd L2 Traffic across L3 Link

best way to fwd Layer 2 traffic across layer 3 link whihc is b/w 6500 and 4500 (multiple distribution) switches. while l2 clients directly connected to 4500 and 6500, can say non routed vlans earlier while it was connected at Layer 2 trunk, but now l3 Link only b/w these switches (6500 & 4500).

2 REPLIES

Re: fwd L2 Traffic across L3 Link

Check into QinQ. I know the 6500 supports it. The 4500 may support it in the new Sup, but I'm not sure, so you'll want to look that up in the Feature Navigator.

http://en.wikipedia.org/wiki/802.1QinQ

Hall of Fame Super Silver

Re: fwd L2 Traffic across L3 Link

Hello Fayyaz,

the best solution would be to revert to a L2 trunk between C6500 and C4500: just add one vlan that will be the equivalent of the current L3 link.

It is th simplest and most efficient solution to extend vlans between two switches.

L2TPv3 may be available on some C6500 but it shouldn't be possible with C4500.

802.1QinQ could be a way to do this by using only one additional vlan (the external "customer vlan-id") on the link but you still need a L2 trunk to carry two vlans: the outer vlan for QinQ and the vlan for the current L3 service.

Hope to help

Giuseppe

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