Hi Ibrahim,
Inter-VLAN routing using an external router can be done in 2 ways in your case, either having 2 access interfaces on the router each belonging to one of the 2 VLANs on the switch and thus the inter-VLAN routing is done by routing the traffic between the 2 interfaces on the router.
The second solution is the router-on-a-stick, this solution reduces the need of multiple interfaces on the router, and thus by making the interface trunk and using subinterfaces each in a VLAN and thus the routing is done between sub-interfaces, which is the preferred solution as it reduces the interfaces required on the router doing the inter-VLAN routing.
I hope that i've been informative.
HTH, please do rate all helpful replies,
Mohammed Mahmoud.
