Linux – Simulating a Low-Bandwidth, High-Latency Network Connection

linuxnetworkingtraffic-shaping

I'd like to simulate a high-latency, low-bandwidth network connection on my Linux machine.

Limiting bandwidth has been discussed before, e.g. here, but I can't find any posts which address limiting both bandwidth and latency.

I can get either high latency or low bandwidth using tc. But I haven't been able to combine these into a single connection. In particular, the example rate control script here doesn't work for me:

# tc qdisc add dev lo root handle 1:0 netem delay 100ms 
# tc qdisc add dev lo parent 1:1 handle 10: tbf rate 256kbit buffer 1600 limit 3000
RTNETLINK answers: Operation not supported

How can I create a low-bandwidth, high-latency connection, using tc or any other readily-available tool?

Best Answer

Aha! It works if we reverse the order of the commands.

tc qdisc add dev lo root handle 1: htb default 12 
tc class add dev lo parent 1:1 classid 1:12 htb rate 20kbps ceil 20kbps 
tc qdisc add dev lo parent 1:12 netem delay 1000ms

https://lists.linux-foundation.org/pipermail/netem/2010-May/001388.html

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