Traffic control on Linux.
Script
The script tc.sh uses the tool tc to emulate bandwidth change.
It reads lines from a file (e.g. bandwidth.txt).
Each line specifies a bandwidth value and how many seconds this bandwidth lasts.
Note
iperf can be used to perform network throughput tests (generate and send data).
For example, run iperf -s -u on server and iperf -c <SERVER> -u -n 1G -b 300k on client.
This will send 1G bytes data to <SERVER> via UDP at the rate of 300kbps.
iftop can be used to display bandwidth usage on an interface.