This bash script offers quick shortcuts to simulate slower network connections. It is useful when you need to simulate a wireless network on a Linux network server, especially when you are using a virtual machine guest on your local machine or in the cloud.
slow 3G # Slow network on default eth0 down to 3G wireless speeds
slow 3G -l 600ms -p 10% # slow network on eth0 and setup latency to 600ms packetloss to 10%
slow reset # Reset connection for default eth0 to normal
slow vsat --latency=500ms # Simulate satellite internet with a high latency
slow dsl -b 1mbps # Simulate DSL with a slower speed than the default
slow modem-56k -d eth0 # Simulate a 56k modem on the eth1 device. eth0 is unchanged.
slow <network-type> [-d device] [-b bandwidth] [-l latency] [-p %drop] [-u %duplication] [-c %corruption] [-r %reordering] [-s self_reset_delay_s]
slow reset
slow status
Use the -s to to trigger slow reset automatically after the timeout. Useful when experimenting with dangerous settings (such as 90% packet loss) and you want to recover the device without rebooting. Also useful for scripting into a test.
slow edge -s 60 &
SLOWPID=$!
ping 8.8.8.8 -c 60
wait $SLOWPID
- v0.5 @sunapi386 implements reset after timeout; to recover device without a reboot
- v0.4 @sunapi386 implements packet duplication, corruption, reordering
- v0.3 @sunapi386 implements the active device selected by default
- v0.2 @aloysius implements packet loss
- v0.1 first version
Richard Bullington-McGuire richard@moduscreate.com wrote the script inspired by a UI suggestion from Mike Schwartz mike@moduscreate.com.
Stack Overflow and Superuser questions that helped:
- http://stackoverflow.com/questions/402377/using-getopts-in-bash-shell-script-to-get-long-and-short-command-line-options/7680682#7680682
- http://superuser.com/questions/147156/simulating-a-low-bandwidth-high-latency-network-connection-on-linux
An Aptivate blog post lent some inspiration, as did this script for throttling bandwidth.