ISL on sub-if

[Jared Carter]

Group-   I have 2 2924 and a 2620 I am trying to practice routing between VLANs.  The trunk between the switches is okay.  When I create the sub-if on the router and try to run encap isl 2, it barks at me that this is an unrecognized command... ie "encapsulation" is not a valid command.  I am running 12.0(3)T3 code on the router.  Am I just missing something obvious?   Thanks   /Jared