Testing SDN behavior with Mininet
Interaction with Mininet
Mininet offers an extensive Python API [11], which you can use to control the overall behavior of each component. You can also use it to define the topology of the network, launch arbitrary processes on hosts, change the parameters of a network interface dynamically, and cycle switch ports off and back on again during emulation. To observe the behavior of a network in a dynamic environment, Mininet even lets you add additional switches, hosts, and network interfaces during an ongoing emulation.
One special feature of Mininet is its interactive command-line (CLI) mode, which allows you to run commands on hosts while the emulation is running. Additionally, it lets you type and run Python code – for example, to change the network topology interactively.
To see whether the OpenFlow controller you are using can cope with dynamically appearing computers, the following example adds a host named H3
to an existing network:
# py net.addHost("H3") <Host H3: pid=1165>
In the next step, you patch the host to S1,
# py net.addLink( net.get("S1"),net.get("H3"))<mininet.link.Link object at 0x13e1c90>
and enable the new interface on S1. To do this, you need to discover the name of the new interface:
# py net.get("S1").intfList() [<Intf lo>, <Intf s1-eth1>, <Intf s1-eth2>, <Intf s1-eth3>]
Armed with the knowledge that the name is s1-eth3
, you can now enable the Mininet interface:
# py net.get("S1").attach("s1-eth3")
Finally, you need to configure the IP address on H3:
# py net.get('H3').cmd("ifconfig h3-eth0 10.0.0.3")
A ping test finally checks to see whether H1 can reach the new host, H3. As Figure 2 shows, the test was successful. For a more detailed demonstration of the capabilities of Mininet, check out the OpenFlow article in this issue.

Conclusions
Mininet is ideal for implementing automated network experiments under realistic conditions. CLI mode makes it a handy tool for rapid prototyping development of controller extensions, and MiniEdit (Figure 3) provides a GUI for creating networks [12].

Because Mininet only runs on one computer, its performance is limited. For example, on an i7 processor clocked at 3.2GHz, Mininet creates a total data throughput of 2.3Gbps. If you want to emulate a network with a higher data volume, you can try out the MaxiNet [13] project, which distributes Mininet across multiple physical computers.
Infos
- Mininet: http://mininet.org
- OpenFlow: https://www.opennetworking.org
- Network namespaces: http://blog.scottlowe.org/2013/09/04/introducing-linux-network-namespaces/
- Nox controller: http://www.noxrepo.org
- Open vSwitch controller: http://openvswitch.org/cgi-bin/ovsman.cgi?page=utilities%2Fovs-controller.8
- OpenFlow 1.0, release notes: http://archive.openflow.org/wk/index.php/OpenFlow_1.0_release_notes
- tc: http://tldp.org/HOWTO/Traffic-Control-HOWTO/software.html#s-iproute2
- Indigo virtual switch: http://www.projectfloodlight.org/indigo-virtual-switch/
- Open vSwitch: http://openvswitch.org
- OpenFlow specs: https://www.opennetworking.org/sdn-resources/onf-specifications/openflow
- Python API for Mininet: http://mininet.org/api/annotated.html
- MiniEdit: http://gregorygee.wordpress.com/category/miniedit/
- MaxiNet: http://www.cs.uni-paderborn.de/?maxinet
« Previous 1 2
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Direct Download
Read full article as PDF:
Price $2.95
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Find SysAdmin Jobs
News
-
Kubuntu Focus Announces XE Gen 2 Linux Laptop
Another Kubuntu-based laptop has arrived to be your next ultra-portable powerhouse with a Linux heart.
-
MNT Seeks Financial Backing for New Seven-Inch Linux Laptop
MNT Pocket Reform is a tiny laptop that is modular, upgradable, recyclable, reusable, and ships with Debian Linux.
-
Ubuntu Flatpak Remix Adds Flatpak Support Preinstalled
If you're looking for a version of Ubuntu that includes Flatpak support out of the box, there's one clear option.
-
Gnome 44 Release Candidate Now Available
The Gnome 44 release candidate has officially arrived and adds a few changes into the mix.
-
Flathub Vying to Become the Standard Linux App Store
If the Flathub team has any say in the matter, their product will become the default tool for installing Linux apps in 2023.
-
Debian 12 to Ship with KDE Plasma 5.27
The Debian development team has shifted to the latest version of KDE for their testing branch.
-
Planet Computers Launches ARM-based Linux Desktop PCs
The firm that originally released a line of mobile keyboards has taken a different direction and has developed a new line of out-of-the-box mini Linux desktop computers.
-
Ubuntu No Longer Shipping with Flatpak
In a move that probably won’t come as a shock to many, Ubuntu and all of its official spins will no longer ship with Flatpak installed.
-
openSUSE Leap 15.5 Beta Now Available
The final version of the Leap 15 series of openSUSE is available for beta testing and offers only new software versions.
-
Linux Kernel 6.2 Released with New Hardware Support
Find out what's new in the most recent release from Linus Torvalds and the Linux kernel team.