Applied Mock Test

Question

Host A is connected to host B with a 100 Mbps link that has a 200 ms one-way latency and transmission delay of 10 sec. How much data can A send to B before B’s first acknowledgement reaches A?

Answer 1

BW=100Mbps

Tt=200ms

Tp=10sec

data that can transfer in 1sec :

Tt=data/BW

So,  data=Tt×BW=200ms×100Mbps=20000000bits

so,  in 1sec we can transfer upto 20000000bits

In 10sec= 20000000/10=2000000bits=2×10*6bits

Answer 2

B’s first acknowledgment reaches A at time = A’s transmission time + RTT = 10 sec + 400ms = 10.4 sec

The link is 100 Mbps,

               In 1 sec ---- 100 * 10^6 bits of data can be sent

               in 10.4 sec --- 100*10^6 * 10.4

                                     = 1400* 10^6 bits can be sent.

Answer 3

 

time before acknowledgement=Tt+2*Tp = 10 sec + 400ms = 10.4 sec
1 sec ---- 100 * 10^6 bits of data can be sent
10.4 sec --- ?
10.4*100*10^6 bits