Trying to create a Etherchannel wtih sub interfaces to support VLAN inter-routing between 3825 ESM module to 3750 G 1RU switch.  I can create the etherchannel between the 3825 and 3750 without subinterfaces and etherchannel works fine and can assign it to a VLAN.

But now the requirement has changed and customer wants to inter-route vlans across the etherchannel.  Took the router on a stick approach across the ehterchannel but subinterface support doesn't seem possible.

I created the etherchannel with subinterfaces fine on the 3825 but when i add the physical interfaces into my ether-channels my config deletes the subinterfaces and defaults back to a plain vanillia port-channel interface. Below are the IOS i'm working with. It appears this configuration isn't supported on the ESM module but no warning given in software

Cisco 3825 Router

IOS: 12.4(15)T12

Cisco 3750G Switch

IOS: 12.2.52-SE(ED)