Awesome
Network Conditions Emulator
This bash script artificially limits bandwidth, delay and loss rate on selected interfaces. It allows traffic shaping on both downlink and uplink. It can enforce shaping on multiple interfaces at a time.
For information and suggestions please write to: martino.trevisan@polito.it
1. Dependencies
This is a bash script to be used in a Linux environment.
It depends on the the package tc. Under the hood it uses the kernel module ifb.
Warning: if you are using nftables, traffic shaping on the Docker interfaces might not work due to routing/NAT issues.
2. Usage
To start traffic shaping, you can run:
sudo ./network_emulator.sh <iface>:<downspeed>:<upspeed>:<rtt>:<loss>
where:
<iface>is the target physical interface you want to alterate<downspeed>is the downlink capacity. Unit must be present, e.g., 20mbit.<upspeed>is the uplink capacity. Unit must be present, e.g., 10mbit.<rtt>is the RTT. Unit must be present, e.g., 50ms. It is enforced on the uplink.<loss>is the loss probability. Must be followed by %, e.g., 10%. Enforced on both up and down link.
You can write multiple <iface>:<downspeed>:<upspeed>:<rtt>:<loss> to configure shaping on multiple interfaces. Under the hood it creates multiple virtual ifb interfaces to shape both down and uplink traffic.
You can omit one or more of <downspeed>, <upspeed>, <rtt>, <loss> to avoid enforcing shaping for those parameters. E.g., you can write a command for enforcing only RTT with: <iface>:::<rtt>:, like wlan0:::50ms:.
To remove all traffic shaping rules, use:
sudo ./network_emulator.sh remove
3. Examples
1. Enforce 20mbit download, 5mbit upload, 20ms RTT and no packet loss on eth0.
sudo ./network_emulator.sh eth0:20mbit:5mbit:20ms:0%
2. Enforce 100ms RTT on eth0.
sudo ./network_emulator.sh eth0:::20ms:
Note that you can omit parameters that you don't want to shape.
3. Enforce 1% packet loss on docker0, docker1 and docker2 (if you are using docker container engine)
sudo ./network_emulator.sh docker0::::1% docker1::::1% docker2::::1%