Computer-Networks

Question 435

Assume that source S and destination D are connected through five intermediate routers R1, R2,R3,R4 and R5. Determine how many times each packet has to visit the Network layer and the Data Link layer during transmission from S to D?

A	Network Layer: 7 times, Data Link Layer: 12 times
B	Network Layer: 5 times, Data Link Layer: 12 times
C	Network Layer: 12 times, Data Link Layer: 12 times
D	Network Layer: 7 times, Data Link Layer: 7 times

Computer-NetworksTCPCIL Part – B

Question 435 Explanation:

The packet will visit network layer 7 times(5 times at router and 1 time at source and another time at destination) , once at each node [S, R, R,R,R,R, D] and packet will visit Data Link layer 12 times. One time at S and one time at D, then two times for each intermediate router R[5*2=10] as data link layer is used for link to link communication.

Correct Answer: A

Question 435 Explanation:

The packet will visit network layer 7 times(5 times at router and 1 time at source and another time at destination) , once at each node [S, R, R,R,R,R, D] and packet will visit Data Link layer 12 times. One time at S and one time at D, then two times for each intermediate router R[5*2=10] as data link layer is used for link to link communication.