I have what is now considered an ancient 2924 switch IOS (tm) C2900XL Software (C2900XL-C3H2S-M), Version 12.0(5)WC16, (Enterprise Edition Software).
It will not let me define one port to be
switchport mode multi switchport multi vlan 10,20
with an error message about this not being possible when there is a "trunk" port defined on the switch.
Is this just some silly arbritary restriction on that model or are there protocol/architectural reasons that prevent combination of trunk ports and multi ports on any/all switches ?