Subinterfaces on ethernet port

I am setting up my lab for the ccnp training and it seems like you cannot configure subinterfaces on an ethernet port.

I am able to configure it without any problem on Fastethernet.
BR2_2611XM#conf t
Enter configuration commands, one per line. End with CNTL/Z.
BR2_2611XM(config)#int fa0/0.34
BR2_2611XM(config-subif)#encap dot
BR2_2611XM(config-subif)#encap dot1Q 34
BR2_2611XM(config-subif)#desc CBT_PR1
BR2_2611XM(config-subif)#ip address 10.1.34.1 255.255.255.252
BR2_2611XM(config-subif)#int fa0/0.24
BR2_2611XM(config-subif)#encap
BR2_2611XM(config-subif)#encapsulation dot
BR2_2611XM(config-subif)#encapsulation dot1Q 24
BR2_2611XM(config-subif)#desc CBT_PR2
BR2_2611XM(config-subif)#ip address 10.1.24.1 255.255.255.252
BR2_2611XM(config-subif)#