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i have a self doubt that till now i solve the TCP question where the sender has $1\hspace{0.1cm}mss$ at starting so during time out  generally reduced the senders window size to $1 \hspace{0.1cm}mss$ but now there is a question that supposes that at starting the  sender has $2 \hspace{0.1cm}mss$ to send and so at time out what will be the sender size i.e we will put it down to $1 \hspace{0.1cm}mss$ or to  $2\hspace{0.1cm}mss$ .........
in Computer Networks
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1
Start with 1 mss

3 Answers

0 votes

If initially sender has window size equal to cwnd = 2MSS then sender will continue with it until congestion detected by -

1) time out occur, then start with slow start phase.

2) 3 ACKs then start with congestion avoidance phase.

In case 1 Sender's threshold will be reduced to half of the current window size $SSthreshold = \frac{1}{2}cwnd$ and again congestion window size will be set to 1 ie $cwnd = 1$.

In case 2 Sender's threshold will be reduced to half of the current window size $SSthreshold = \frac{1}{2}cwnd$ and congestion window size will be set to sender's threshold ie $cwnd = SSthreshold$. It then start congestion avoidance phase.

For more reference refer

https://gateoverflow.in/2156/gate2012-45

PS :

http://inst.eecs.berkeley.edu/~ee122/fa06/notes/18-Congestion-2up.pdf

 

edited by
0
i am asking about is the default value to start after tym out is 1MSS or not because the link u provided has many solution which says it will be 1mss nd many says it will be 2mss after tym out ......
1
It will be 1MSS only after time out occurs
0
READ THE FIRST ANSWER IN LINK IT SAYS 1MSS ALWAYS
0 votes
It will start from initial that is 2 MSS not 1 MSS when timeout occurs. (put down to 2 MSS not 1 MSS)
0 votes
In question if its mentioned that window size is 1MSS then take 1MSS else if 2MSS mentioned then take 2MSS.

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