Provided by: mahimahi_0.98-1.1_amd64 
NAME
mahimahi - lightweight, composable network-emulation tools
link emulation: mm-delay, mm-loss, mm-onoff, mm-link
analysis scripts: mm-throughput-graph, mm-delay-graph
observation: mm-meter
record and replay multi-origin websites: mm-webrecord, mm-webreplay
DESCRIPTION
mahimahi is a suite of user-space tools for network emulation and analysis.
Each mahimahi tool spawns a lightweight container, generally connected to the outside via a synthetic
network device that observes packets in transit or emulates a desired behavior.
The tools are composable so that a series of emulated network effects can be chained together, with
mahimahi containers nested inside each other. Each tool takes an optional command to execute, so it is
possible to create a series of nested containers with one command line.
LINK EMULATION TOOLS
mm-delay delay [command...]
Every packet is delayed by the specified delay (in milliseconds) entering and leaving the
container.
mm-loss uplink|downlink rate [command...]
Packets are lost at the given rate either when leaving (uplink) or entering (downlink) the
container. rate is a number between 0 and 1.
mm-onoff uplink|downlink mean-on-time mean-off-time [command...]
The uplink or downlink will be intermittent and will switch between connected and disconnected
states according to a Poisson point process with specified average durations spent "on" and
"off".
mm-link [--uplink-log=filename] [--downlink-log=filename] [--meter-uplink] [--meter-uplink-delay]
[--meter-downlink] [--meter-downlink-delay] [--once] uplink-filename downlink-filename
[command...]
mm-throughput-graph
mm-delay-graph
Emulates a throughput-limited link with a specified packet-delivery schedule and analyzes
the resulting performance. See mm-link(1).
OBSERVATION TOOLS
mm-meter [--meter-uplink] [--meter-downlink] [command...]
Displays an animated live plot of the transfer rate entering or leaving the container.
RECORD AND REPLAY WEBSITES
mm-webrecord directory [command...]
Transparently proxies outgoing HTTP and HTTPS connections, saving the requests,
corresponding responses, and IP address of each Web server contacted in the given directory.
mm-webrecord uses a self-signed TLS certificate in its HTTPS proxy, causing typical Web
browsers to reject it. For testing or debugging purposes, this behavior can usually be
turned off, e.g.: with the --no-check-certificate option to wget(1) or the --ignore-
certificate-errors option to chromium-browser(1).
mm-webreplay directory [command...]
Replays a saved session from a previous run of mm-webrecord. Unlike most mahimahi tools,
the mm-webreplay container does not have a network connection to the outside world. Instead,
it has dummy network interfaces bound to each IP address on which a Web server in the saved
session had answered a request. mm-webreplay runs an apache2(8) Web server bound to each
such IP address inside the container. Each Web server emulates the corresponding server from
the saved session. When receiving a request that matches one in the directory, the
corresponding apache2 replies with the same reply as previously captured.
mm-webreplay can be used to measure the performance of Web browsers on complex websites and
the effect of changes in Web protocols (e.g. HTTP, HTTP/2, SPDY, QUIC). Unlike tools like
web-page-replay, mm-webreplay preserves the sharded structure of a website, binds to the
actual IP addresses that the real website used, and serves requests from real Web servers.
ENVIRONMENT
The MAHIMAHI_BASE environment variable is set to an IP address of the host, outside any container. This
can be used to conduct scripted measurements over a series of mahimahi containers chained together.
EXAMPLES
To spawn a shell with a delayed, lossy link to the Internet:
$ mm-delay 50 mm-loss uplink 0.2
[delay 50 ms] [loss up=0.1] $
To run ping over the same link:
$ mm-delay 50 mm-loss uplink 0.2 sh -c 'ping -c 10 -n $MAHIMAHI_BASE'
PING 100.64.0.1 (100.64.0.1) 56(84) bytes of data.
64 bytes from 100.64.0.1: icmp_seq=1 ttl=63 time=101 ms
64 bytes from 100.64.0.1: icmp_seq=2 ttl=63 time=100 ms
64 bytes from 100.64.0.1: icmp_seq=4 ttl=63 time=101 ms
64 bytes from 100.64.0.1: icmp_seq=5 ttl=63 time=100 ms
64 bytes from 100.64.0.1: icmp_seq=7 ttl=63 time=101 ms
64 bytes from 100.64.0.1: icmp_seq=8 ttl=63 time=101 ms
64 bytes from 100.64.0.1: icmp_seq=9 ttl=63 time=101 ms
64 bytes from 100.64.0.1: icmp_seq=10 ttl=63 time=101 ms
--- 100.64.0.1 ping statistics ---
10 packets transmitted, 8 received, 20% packet loss, time 8999ms
rtt min/avg/max/mdev = 100.910/101.009/101.092/0.279 ms
To record a page load from www.nytimes.com:
$ mm-webrecord /tmp/nytimes chromium-browser --ignore-certificate-errors --user-data-dir=/tmp/nonexistent$(date +%s%N) www.nytimes.com
The use of --user-data-dir=/tmp/nonexistent$(date +%s%N) is to prevent the browser from reusing an
existing chromium-browser process.
To make Chrome retrieve the saved website over a delayed, lossy link whose throughput is limited to 1
full-sized packet per millisecond:
$ mm-webreplay /tmp/nytimes mm-delay 50 mm-loss uplink 0.1 mm-link <(echo 1) <(echo 1) -- chromium-browser --ignore-certificate-errors --user-data-dir=/tmp/nonexistent$(date +%s%N) www.nytimes.com
To emulate a variable cellular network and visualize a process's use of the network:
$ mm-delay 20 mm-link --meter-all /usr/share/mahimahi/traces/Verizon-LTE-short.up /usr/share/mahimahi/traces/Verizon-LTE-short.down
[delay 20 ms] [link] $
SEE ALSO
mm-link(1)
Project home page: http://mahimahi.mit.edu
AUTHOR
Mahimahi was written by Ravi Netravali, Anirudh Sivaraman, Greg D. Hill, Deepak Narayanan, and Keith
Winstein.
BUGS
Please report bugs to mahimahi@mit.edu.
March 2015 MAHIMAHI(1)