If you want terribad network conditions, you can use cellsim
(instructions at http://alfalfa.mit.edu/) which will let you replay actual
network condition traces from cellular links (including such awesome
properties as intermittent 60+s latency).
--Quentin
On Sat, 23 May 2020, Jehan Tremback wrote:
Yes, we have used tc netem to successfully make a connection bad.
--
Jehan Tremback
jehan@xxxxxxxxxx
On Sat, May 23, 2020, at 1:22 PM, Erik Auerswald wrote:
Hi,
recently someone asked about a script for simulating or emulating degraded
network conditions. I could not provide an answer, because I do not have
something like that available, yet.
But I have just read about "Comcast" which seems to do just that:
https://github.com/tylertreat/Comcast
The README.md contains information on how to use iptables and/or tc
directly instead of through Comcast as well:
"""
Linux
On Linux, you can use iptables to drop incoming and outgoing packets.
$ iptables -A INPUT -m statistic --mode random --probability 0.1 -j DROP
$ iptables -A OUTPUT -m statistic --mode random --probability 0.1 -j DROP
Alternatively, you can use tc which supports some additional options.
$ tc qdisc add dev eth0 root netem delay 50ms 20ms distribution
normal
$ tc qdisc change dev eth0 root netem reorder 0.02 duplicate 0.05
corrupt 0.01
To reset:
$ tc qdisc del dev eth0 root netem
"""
-- https://github.com/tylertreat/Comcast#linux
I have not tested this, but it seems to provide a starting point for
experimentation.
HTH,
Erik
--
To a first approximation, we can say that accidents are almost always
the result of incorrect estimates of the likelihood of one or more things.
-- C. Michael Holloway, NASA
