Applied Course Test Series

Question

Q.8)
Consider the effect of using additive increase multiplicative decrease (AIMD) on a line with propagation delay of 10ms.The receive window is 24KB and the maximum segment size is 2KB.How long does it take to send full window size segment in ms initial threshold of 20KB?

 

   A) 100 ms

B

 

  120 ms

C

 

     80 ms

D

 

   140 ms

Answer 1

When the ACK is received of the last segment then we can say that there has been a successful transmission, so for that we need to consider the Round Trip Time.

RTT= 2*Propagation Delay= 2*10=20 ms

Now initial in slow start phase W(c)=congestion window=1 MSS

The congestion window changes as follow( here | represents one RTT):
1 | 2 | 4 | 8 | 10 (congestion threshold reached) | 11 | 12 |
As you can see that 7 RTTs were required hence,

total time= 7*RTT=7*20=140 ms.

Let me know if there are any issues!