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Formula for TCP Congestion window on the sender side

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I wanted to do a TCP congestion window analysis. As shown in the 7th column of the csv file found in this link- we can see the congestion window increases and sometimes decreases. But I don't seem to understand the pattern when it decreases, why it increases by a certain number (for example: from 25 to 29). Is it because of the sequence number or?

Is there any formula that calculates this?

asked 08 Mar '17, 01:44

armodes's gravatar image

armodes
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accept rate: 0%

edited 09 Mar '17, 11:33


One Answer:

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Nice File. How did you create it? Normally the CWND and SSTHRESH are hidden.

So if the sender sends a packet the cwnd is reduced by the amount of the bytes of the segments. If he receives an ACK for that segment the CWND is increased by the ACKed data. The exactly size and behaviour of the cwnd depends also on the congestion algorithm which is actually used.

http://packetlife.net/blog/2011/jul/5/tcp-slow-start/

answered 08 Mar '17, 12:40

Christian_R's gravatar image

Christian_R
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accept rate: 16%

edited 10 Mar '17, 01:16