Test bandwidth between two hosts

Install iperf CLI tool:
apt-get install iperf
or
download for windows from https://iperf.fr/

Run iperf as server on one host(192.168.0.1):
iperf -s

Run client on other host(192.168.0.100):

iperf -c 192.168.0.1 -t 30 -i 5

Output:
------------------------------------------------------------
Client connecting to 192.168.0.1, TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  3] local 192.168.0.100 port 49363 connected with 192.168.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 5.0 sec  53.8 MBytes  90.2 Mbits/sec
[  3]  5.0-10.0 sec  55.0 MBytes  92.3 Mbits/sec
[  3] 10.0-15.0 sec  54.2 MBytes  91.0 Mbits/sec
[  3] 15.0-20.0 sec  55.2 MBytes  92.7 Mbits/sec
[  3] 20.0-25.0 sec  54.1 MBytes  90.8 Mbits/sec
[  3] 25.0-30.0 sec  54.1 MBytes  90.8 Mbits/sec
[  3]  0.0-30.0 sec   327 MBytes  91.3 Mbits/sec

Use parameter -w 1m to specify TCP window size .

Detailed information: http://openmaniak.com/iperf.php
Information about TCP windowing: https://www.slashroot.in/