test book

Question

Comments

the sequence number will be 0 to 7 it can be represented with 3 bits the only relation is max window size can be

2³ - 1 = 7 so 3 is the answer

Answer 1

Window Size = 7.

Sequence number = 3 bits,hence 8 frames can be numbered from 0-7 and again the number repeats for the next set of frame. 

7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 -> Initial configuration at sender (Bolded ones are the frames within the window)

ACK3 is not received by A, but ACK4 is received by A which indicates all the frames till frame 4 have been received correctly.

At this point the sender configuration is: 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5.

Now frame 5 is lost, so the whole window i.e. 5 6 7 0 1 2 3 is resent, which is option A.