Can a port channel on a 6500 have both L3 & L2 subinterfaces?

[jkeeffe]

The access-layer 6500 is sup32, the distribution layer 6500 is Sup720, both running 12.2(33)SXH8. The uplink is a two-port gig portchannel. Right now the uplink is a L3 /30.  I want to carry a vlan up between the two 6500s and was hoping I could subinterface the portchannel with one L3 and one L2 subinterface. (I also need to keep the L3 /30 in place also.) I'm not having much succes with this as the subinterface doesn't seem to have any 'switch...' commands available.

Is it not possible to have both a L3 and L2 subinterface on the same portchannel on a 6500?

Is there another way to keep the /30 uplink and also have the same vlan on both 6500 - through the same portchannel?

[Jon Marshall · Accepted solution]

I don't think you will be able to do it with subinterfaces because subinterfaces are not L2.

Only way i can think to do this is to -

1) make the link a L2 etherchannel trunk and allow 2 vlans eg,. vlan 10 and vlan 11

2) vlan 11 is your L2 vlan

3) vlan 10 would be your "L3 vlan" ie. on both ends of the link -

int vlan 10

ip address x.x.x.x   <-- where the IP address is the one currently assigned to the actual portchannel.

You would then peer (in terms of routing) on the vlan 10 interfaces. All vlans except vlan 11 would then need to use vlan 10 to route between switches. Only vlan 11 is allowed to switch at L2 between switches. For this to work you have to  make sure, as mentioned above. that you only allow the 2 vlans on the trunk link.

Edit - if you don't like the above the only other thing would to be use a spare fibre if you have it and configure it as a switchport at both ends in vlan you want to L2 switch between switches.

Jon