Use iperf and ping at the same time mininet

Question

I just started a course on Computer Networks and my first assignment provides me with mininet script of a simple star topology, and asks me run an iperf measurement between h1 and h2. While the iperf is running I should test the ping between h3 and h4.

My question is that how do I make iperf measuring the data to run in background so I can test the ping, as I can not input when the iperf is running also cant open new terminal for mininet.

Giuseppe Giuseppe · Accepted Answer · 2020-09-16T11:17:39

You have two options:

1 - use the python API

2 - run parallel processes from the CLI

I am going to explain the second option, since you are using the CLI for your experiments.

First step: run Mininet with the single(star) topology.

giuseppe@raspberrypi:~ $ sudo mn --topo single,4
*** Creating network
*** Adding controller
*** Adding hosts:
h1 h2 h3 h4
*** Adding switches:
s1
*** Adding links:
(h1, s1) (h2, s1) (h3, s1) (h4, s1)
*** Configuring hosts
h1 h2 h3 h4
*** Starting controller
c0
*** Starting 1 switches
s1 ...
*** Starting CLI:
mininet>

if you want to do an iperf from h1->h2, you need the IP of h2, you can find it with ifconfig

mininet> h2 ifconfig
h2-eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.0.0.2  netmask 255.0.0.0  broadcast 10.255.255.255
        inet6 fe80::b87a:eaff:fec1:64a0  prefixlen 64  scopeid 0x20<link>
        ether ba:7a:ea:c1:64:a0  txqueuelen 1000  (Ethernet)
        RX packets 98  bytes 14845 (14.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 11  bytes 866 (866.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Start the server in h2 and log the stdout end stderr in the h2.log file

mininet> h2 iperf -s &> h2.log &

run the iperf client from h1 to h2(ip=10.0.0.2) and save the output in the h1.log file(in this case, I run it for 120 seconds, but you can adjust it)

mininet> h1 iperf -t 120 -c 10.0.0.2 &> h1.log &

Now you can run the ping, while the iperf is executing in background

mininet> h3 ping h4

You can check the logs opening another shell or after completing the experiment

mininet> h3 ping h4
PING 10.0.0.4 (10.0.0.4) 56(84) bytes of data.
64 bytes from 10.0.0.4: icmp_seq=1 ttl=64 time=30.7 ms
64 bytes from 10.0.0.4: icmp_seq=2 ttl=64 time=1.84 ms
64 bytes from 10.0.0.4: icmp_seq=3 ttl=64 time=0.393 ms
64 bytes from 10.0.0.4: icmp_seq=4 ttl=64 time=0.387 ms
^C
--- 10.0.0.4 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 73ms
rtt min/avg/max/mdev = 0.387/8.327/30.692/12.925 ms
mininet> exit
*** Stopping 1 controllers
c0
*** Stopping 4 links
....
*** Stopping 1 switches
s1
*** Stopping 4 hosts
h1 h2 h3 h4
*** Done
completed in 473.135 seconds
giuseppe@raspberrypi:~ $
giuseppe@raspberrypi:~ $ ls
h1.log  h2.log

Use iperf and ping at the same time mininet

2 Answers