Emulationtest

Emulation Test

Test Topology

<topology name="dummynet_test">
	<device id="openvz1" pos="189,242" template="debian-6.0-standard_6.0-2_i386" type="openvz">
		<interface id="eth0" use_dhcp="true"/>
		<interface id="eth1" ip4address="10.1.1.1/24"/>
	</device>
	<device id="openvz2" pos="408,244" template="debian-6.0-standard_6.0-2_i386" type="openvz">
		<interface id="eth0" use_dhcp="true"/>
		<interface id="eth1" ip4address="10.1.1.2/24"/>
	</device>
	<connector id="switch1" pos="298,245" type="switch">
		<connection device="openvz1" interface="eth1"/>
		<connection device="openvz2" interface="eth1"/>
	</connector>
	<connector id="internet1" pos="303,109" type="real">
		<connection device="openvz1" interface="eth0"/>
		<connection device="openvz2" interface="eth0"/>
	</connector>
</topology>

Loss emulation

Commands

On the server:

iperf -u -s

On the client:

iperf -u -c IP -i 1 -t 60 -b 50M

Results

Configured loss	Measured loss
0%	0%
0.125%	0.122%
0.25%	0.244%
0.5%	0.499%
1%	1.03%
2%	2.03%
5%	5.01%
10%	9.94%
20%	20.08%
40%	39.82%
80%	80.00%

Delay emulation

Commands

On the client:

ping IP -c 100

Note: The configured delay is half of the configured RTT

Results

Configured RTT	Mean RTT	StdDev
2000 ms	2000.001 ms	1.718 ms
1000 ms	1000.975 ms	0.532 ms
500 ms	499.942 ms	0.679 ms
200 ms	199.979 ms	0.278 ms
100 ms	99.942 ms	0.396 ms
50 ms	49.973 ms	0.311 ms
20 ms	19.975 ms	0.150 ms
10 ms	9.974 ms	0.132 ms
4 ms	3.978 ms	0.070 ms
2 ms	1.974 ms	0.078 ms
0 ms	0.394 ms	0.078 ms

Bandwidth emulation

Commands

iperf -u -s -i 1 -y c > data 
head -n 60 < data | cut -d, -f 9 > data2
./analyze.pl data2

On the client:

iperf -u -c 10.1.1.2 -t 60 -b 1000M -i 1

analyze.pl:

#!/usr/bin/env perl
use strict;
use warnings;
use Math::NumberCruncher;
my @data;
open (IN, "<", "$ARGV[0]") or die ("Cannot open $ARGV[0]: $!\n");
while (<IN>) {
  push @data, $1 if (/(\d+)/);
}
close (IN);
printf("Mean: %f\tMedian: %f\tStdDev: %f\n",
Math::NumberCruncher::Mean(\@data),
Math::NumberCruncher::Median(\@data),
Math::NumberCruncher::StandardDeviation(\@data));

Results

Note that TCP/IP can not reach the available bandwidth due to protocol overhead and StdDev of about 5 Kbits/sec is expected because of the packet size of 1470 bytes and the measurement interval of 1 second.

Configured	Mean	%	StdDev
unlimited	476 Mbits/sec		21.3 Mbits/sec
100 Mbits/sec	98.4 Mbits/sec	98.4%	209.2 Kbits/sec
50 Mbits/sec	49.1 Mbits/sec	98.2%	40.0 Kbits/sec
20 Mbits/sec	19.6 Mbits/sec	98.0%	5.54 Kbits/sec
10 Mbits/sec	9.82 Mbits/sec	98.2%	5.87 Kbits/sec
5 Mbits/sec	4.91 Mbits/sec	98.2%	5.20 Kbits/sec
2 Mbits/sec	1.96 Mbits/sec	98.0%	3.53 Kbits/sec
1 Mbits/sec	982 Kbits/sec	98.2%	5.85 Kbits/sec
500 Kbits/sec	491 Kbits/sec	98.2%	5.20 Kbits/sec
200 Kbits/sec	196.4 Kbits/sec	98.2%	5.39 Kbits/sec
100 Kbits/sec	98.2 Kbits/sec	98.2%	5.61 Kbits/sec
50 Kbits/sec	49.1 Kbits/sec	98.2%	4.55 Kbits/sec
20 Kbits/sec	19.8 Kbits/sec	99%	5.47 Kbits/sec
10 Kbits/sec	10 Kbits/sec	100%	4.72 Kbits/sec