I have a problem to assign a vlan ID with a particular ether port rather than creating a new interface, hence making the router act as a switch. Is this possible with a routerboard750GL?

Regards,
chris.

Nope, it is a router not a switch. Each VLAN added to an interface is treated as a separate routed interface. If you wanted a switch, get a switch.

Hi
i think hare is a chance to add vlan or vlans on one interface

create vlan/vlans
create bridge
in bridge ports, add vlans and that interface which you want to use for vlans

Winbox -> SWITCH TAB.

You can VLAN pre-tag / untag there. You may also use the terminal session(a few things appear to be missing in winbox).

Make sure you take a look at RULE -> Action tab, and use `copy to cpu' | redirect to CPU or MIRROR as necessary, as this switch command `can' disconnect the interface from the CPU(routerOS) if your not careful and you wont be able to `get into' the unit from the particular port if you config the switch port/interface wrong..