Connecting cisco WS-C2916M-XL to a 2948G L3

[tuks]

I want to connect the two switch together. On the 2948G L3 port I have configured a port such as this

interface FastEthernet7
description 2916XL Switch
no ip address
no ip directed-broadcast
duplex full
!
interface FastEthernet7.1
encapsulation isl 2
no ip redirects
no ip directed-broadcast
bridge-group 2

This port will be used to connect to my WS-C2916M-XL switch. I did try to configure fastethernet 0/1 to switchport mode trunk so that I can then connect this switch to my 2948G L. I cant get this. Is this something to do with the IOS version of my 2916 switch or is there an alternative command

Please help