Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

questioned mentioned in \"i\": We are using TCP Reno. ssthresh is set to 16. Ass

ID: 3703191 • Letter: Q

Question

questioned mentioned in "i":

We are using TCP Reno. ssthresh is set to 16. Assume no errors.

a)(5 pts) Starting from a window size of 1, calculate how many round you need to send 30 packets, as the window size (cwnd) grows each round. Subtract that from your remaining total to show how many packets remain in the last column:

b)If you had 30 packets to send instead of 31, would anything change?

For the next questions, assume MSS is 1000 bytes, cwnd is 10,000 bytes f. How many packets can be sent in one window's worth of transmissions? g. When you are in slow start, and you receive an ACK, how much does cund grow? When you are in congestion avoidance, and you receive an ACK, by how much does each ACK cause the value of cwnd to increase? Assume MSS-1000 bytes, swnd-10,000 bytes, and show the equation and result. h. i. If you had 50 packets to send, how many rounds would you continue in the problem above (part b)? How big is the window in the last transmission?

Explanation / Answer

Solution:

a)

below is the table for how the cwnd will grow

#Round

Packets

#packets sent

packets remaining

1

1

1

30

2

2

3

28

3

3

6

25

4

4

10

21

5

5

15

16

b)

No, nothing will change

f)

The number of packets which can be sent in one window's worth of transmissions=

Since MSS is 1000 bytes, and each packet is of size 1000 bytes.

After getting the acknowledgment the cwnd size increases by 1 packet

which is going to be

1000 bytes.

g)

After getting the ACK the cwnd grow by one

and again we will start to increase the size of the cwnd, by cwnd = cwnd + 1, at each recieved ACKs.

h)

In the congestion avoidance phase the size of the cwnd increases by

cwnd = cwnd + 1/cwnd

MSS = 1000 bytes

cwnd = 10000 + 10000/1000 = 10010

i)

then the congestion window will become 10500 bytes large

I hope this helps if you find any problem. Please comment below. Don't forget to give a thumbs up if you liked it. :)

#Round

Packets

#packets sent

packets remaining

1

1

1

30

2

2

3

28

3

3

6

25

4

4

10

21

5

5

15

16