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A computer on a $6-Mbps$ network is regulated by a token bucket. The token bucket is filled at a rate of $\text{1 Mbps}$. It is initially filled to capacity with $\text{8 megabits}$.
If the system is initially idle for $\text{2 sec}$ then how long can the computer transmit at the full $\text{6 Mbps}$ speed?
  1. $\text{1.6 sec}$
  2. $\text{2.6 sec}$
  3. $\text{3.6 sec}$
  4. $\text{4 sec}$
asked in Computer Networks by Boss (17.2k points) | 118 views

If the system is initially idle for 2 sec 

can someone please explain what is significance of this line  

shouldnt the ans be 3.6 and not 1.6sec as the system is idle for 2 seconds so shouldnt we count that time too?
In question it is asking how ling it will take to transfer at with 6Mbps speed so it should be 1.6ns and if total time to transfer is asked then i think answer will be 3.6ns.
"Bucket is filled to capacity". Assuming that it means bucket is full, Even if system is idle for 2sec, New tokens won't be generated. So 8/6-1= 8/5=1.6 is the correct answer.
someone please explain in detail

input flow = output flow.

=> C+ (R*S) = M*S

C = initial capacity = 8 Mb

R = Token filling Rate = 1 Mbps

M = Output Rate = 6 Mbps

S = Busty Traffic transmit time.

=> 8 + (1*S) = 6*S

=> S = 8/5 = 1.6.

=> it took 1.6 sec to transfer the data.

the system is initially idle for 2 sec  this line is for creating confusion. System was idle or not why should we care.

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