Unanswered Question

hi! i've a pair of old 6509 that's connected to a new pair of 6509e. Currently all the L3 routing is at the old core. We are in process of migrating these L3 GW to the new Core vlan by vlan. I've these 2 pairs of core switches connected by a L2 link right now and i tried to create a new vlan interface on the new core but that vlan gw doesn't seems to work. What need to be done in the new core for the new vlan gw to work? (the interface is up) We are not using any routing protocol at the moment.

Pls advise. Thanks.

I have this problem too.
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Giuseppe Larosa Wed, 10/28/2009 - 05:04

Hello David,

depending on your VTP mode:

the L2 vlan X has to be created in a VTP server.

the L3 vlan can be created on one or multiple devices.

you need a L2 path (an access port or a L2 trunk) to give to the SVI the capability to reach the outside world.

so that vlan need to be permitted on trunks to old core switches.

Hope to help


hi! thanks for the reply.....the L2 vlan and L3 vlans have been created. The links between the old cores and the new cores are L2 trunk link.

I can actually see the new vlan in the new core and all the edge switches, but doesn't seems to able to ping the vlan interfaces on the new core switch.

what did i miss out here?


Giuseppe Larosa Wed, 10/28/2009 - 07:37

Hello David,

>> We are not using any routing protocol at the moment.

so you need static routes on old core switches and also you need to place SVI ip addresses of new swiches in a common L2 vlan to provide a valid ip next-hop for the static routes.

you can check then with sh ip arp x.y.z.k if the MAC entry exists and it is correct.

Hope to help



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