Log In
1 vote

The data link layer uses a fixed-size sliding window protocol, where the window size for the connection is equal to twice the bandwidth-delay product of the network path. Consider the following three scenarios, in each of which only the given parameter changes as specified (no other parameters change). For each scenario, explain whether the throughput (not utilization) of the connection increases, decreases, remains the same, or cannot be determined:

  1. the packet loss rate $L$ decreases to $L/3$;
  2. the minimum value of the round trip time $R$ increases to $1.8R$;
  3. the window size $W$ decreases to $W/3$
in Computer Networks 183 views
1. loss rate decreases ie, efficiency  increases, throughput = efficiency * bandwidth,so throughput increases.

2.RTT  increases means Tp increases, so windowsize =1 + Tt/Tp decreases , as throughput=L/1+2a ,so throughput increases.

3.Windowsize decreases ,so throughput will increase.considering Throughput =Length of the packet/window size)

Correct me if I am wrong.

@Akash Ghosh @Arjun @srestha 

There is an ambiguity in the Question. Throughput is also Called Bandwidth Utilization. They haven't mentioned which Utilization it is, Line Utilization or Bandwidth Utilization



@Akash Ghosh

Window size is $1 + Tp/Tt$

They asked for throughput.So,utilization means efficiency , what I think

I think the you have written the formula wrong . In efficiency for the sliding window protocol we follow the formula n = N/(1+2a) where a = Tp/ Tt. Where N = The sliding window size in the sending side.

b) Now as RTT increases propagation time also increases , so the a increases and efficiency(n) decreases. We know Throughput = Efiiciency * Bandwidth. So as Efficiency decreases, Throughput also decreases.

c) As the window size(N) decreases so generally efficiency also decreases. Hence Throughput decreases.

Please log in or register to answer this question.

Related questions

0 votes
2 answers
Consider two $n \times 1$ vectors $u$ and $v$ , stored as table $U(\text{ind,val})$ and $V(\text{ind,val})$ with the same schema A row $(i,u_i)$ of table $U$ specifies the $i^{th}$ element of vector $u$ has value $u_i$ (similarly for $v$, ... $u + v$ of the two vectors $u$ and $v$. Explain your solution.
asked May 12, 2019 in Databases akash.dinkar12 221 views
0 votes
2 answers
Consider a $5$ ... $\text{(in ns)}$ needed to execute the program.
asked May 12, 2019 in Operating System akash.dinkar12 264 views
1 vote
2 answers
A context switch from a process $P_{old}$ to a process $P_{new}$ consists of the following steps: Step I:saving the context of $P_{old}$; Step II: running the scheduling algorithm to pick $P_{new}$; Step III: restoring the saved context of $P_{new}$. Suppose Steps I and ... same instant in the order $P_1, P_2, . . . , P_k;$ each process requires exactly one CPU burst of $20$ms and no I/O burst.
asked May 12, 2019 in Operating System akash.dinkar12 250 views
0 votes
1 answer
The following function computes an array $SPF$, where, for any integer $1 < i < 1000$, $SPF[i]$ is the smallest prime factor of $i$. For example, $SPF[6]$ is $2$, and $SPF[11]$ is $11$. There are five missing parts in the following code, commented as $/* Blank */$. For each of them, copy the entire ... ; j < 1000; j+= i) { /* Blank 4 */ if (SPF[j] == j) { SPF[j] = _____; /* Blank 5 */ } } } } }
asked May 12, 2019 in Algorithms akash.dinkar12 140 views