Assume that Source S and Destination D are connected through an intermediate router R. How many times does a packet have to visit the network layer…

Assume that Source S and Destination D are connected through an intermediate router R. How many times does a packet have to visit the network layer and data link layer during a transmission from S to D?

(Diagram: a simple chain S — R — R — D, where S and D are drawn as squares and the two R nodes as circles, connected in a straight line by line segments.)

1. a) Network layer -4 times, Data link layer -4 times
2. b) Network layer -4 times, Data link layer -6 times
3. c) Network layer -2 times, Data link layer -4 times
4. d) Network layer -3 times, Data link layer -4 times