How many physical interfaces are required to perform inter-VLAN routing with traditional inter-VLAN routing?
In traditional inter-VLAN routing (also known as "router-on-a-stick"), only one physical interface is required on the router.
However, this single physical interface needs to be configured with multiple sub interfaces, each corresponding to a different VLAN. The router uses these sub interfaces to route traffic between VLANs. The configuration involves:
One physical interface on the router (e.g., GigabitEthernet0/1).
Multiple sub interfaces (e.g., GigabitEthernet0/1.10, GigabitEthernet0/1.20) corresponding to different VLANs.
Each sub interface is assigned an IP address in the respective VLAN's subnet. This setup enables inter-VLAN routing by allowing the router to route traffic between the VLANs using a single physical interface.