TCP newreno congestion control Window Scaling simulate

asked 2022-11-16 13:53:41 +0000

lfyao gravatar image

Hello, I am trying to understand how congestion control works by using the ipfw to simulate the network condition.

the condition are as follows. bandwidth = 4Mbps/s delay = 100ms newreno, packet loss rate = default

You can see that according to the graph#1, according to my understand, if there is a timeout, the window size will drop to 1.

image description

image description

but according to the dump I get from the wireshark window scaling, at time 1.5 instead of timing out, it seems to sudden drop to zero, then there is a steep increase, then another drop. What does it mean? Is it a fast recovery?

And also the marked part in color according to my understanding is (red = Slow Start, Blue = Congestion Avoidance, Green = Fast Recovery)

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Also, the pcap file can be seen here link text

with filter ip.src== && ip.dst== && tcp

and the chart of Length 1514

lfyao gravatar imagelfyao ( 2022-11-16 14:32:19 +0000 )edit