What the difference between a physical and virtual(logical?) network interface from the point of view of the kernel? How does it access an existing physical int differently compared to a virtual interface that only exists inside the Kernel. And how does it reroute the traffic from a virtual interface (lets say a newly created tunnel) to that one interface that actually has a networking card assigned to it and can sent/recieve packets?

Wasn't sure if it should go to the networking subforum or kernel one, but as I got very few replies in networkign I thought I would post this one here for a change