line efficiency

Question

solve in detail...........

Answer 1

Line efficiency = throughput / bandwidth ----- (1)

Throughput = window size / rtt ------(2)

So throughput = 65535/40 * 10^3 = 1638375

And bandwidth = 512 Mbps

 

Therofore Line efficiency(in %) = 2.56

Comments

Thanx

Answer 2

Maximum window size= $RTT*BW=512*10^6*40*10^{-3}$bits=$20480*10^3$ bits

As mentioned in question, We are sending $65,535$ Bytes whereas we could have sent above mentioned number of bytes

$\therefore$ Line efficiency=$\frac{65,535*8}{20480*10^3}*100\%=2.559\%$

Comments

@Sukannya then why did you not include TT in RTT? Without a packet is transmitted ACK cannot arrive - so for ACK to reach back, TT time must also be passed.

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Sir, here first thing is total window size is given, so how can we find packet size in order to find transmission time from it? And as one way delay is given, I read somewhere that Tt is already included in it...!

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Yes, I missed that. But if a packet size is given you must add it.

Answer 3

line efficiency=  Tt/(Tt+2Tp)

                     =1.023/(1.023+2*20) =0.0255= 2.55%