Tutorial 1: "Simple" Controllers

We can run the OF controller on the sb9 console or on one of the nodes as they each have access the the OpenFlow switch management interface. In this document, we are about to use two distinct controllers, one from the OpenFlow reference System and another from NOX-core, for management of the setup. These may be even installed in your userspace if you wish to run one of these controllers from the Console (normaly they are installe under root account on one of the nodes in the sb9).

Controller on a node

The software can be downloaded from the following places:

• OpenFlow reference system: ​http://www.openflowswitch.org/wp/downloads/
• NOX-core: ​http://noxrepo.org/wp/

The former is a simple implementation that comes with a few tests; latter is a full-blown network operating system/ development tool that comes with a Network API that can be used to write and develop your own controller in C++ or Python.

Both can also be installed using Git. Git can be installed with the following command:

apt-get install git-core   

Installing the OpenFlow Reference System (old)

While presented, it is not recommended to install from tarball. The detailed instructions may be found here: ​http://www.openflowswitch.org/wp/getstarted/

1. Download software and required packages. If using git:

   sudo apt-get install git-core automake m4 pkg-config libtool
   git clone http://openflowswitch.org/openflow
   cd openflow
   ./boot.sh
   

if installing from tarball:

mkdir openflow
cd openflow
wget http://openflowswitch.org/downloads/openflow-0.9.0.tar.gz
tar xzf openflow-0.9.0.tar.gz
cd openflow-0.9.0
sudo apt-get install gcc linux-headers-`uname -r`

2. Make and install.

   ./configure --with-l26=/lib/modules/`uname -r`/build
   make
   make install
   

Installing NOX

It is not only recommended but also much simpler to use git to install NOX. Therefore the following instructions assume you are using git. The full instructions are found at noxrepo.org: ​http://noxrepo.org/manual/installation.html

Dependencies
NOX requires the following packages to be installed on the Console:

• GNU Libtool (libtool)
• Boost C++ libraries (libboost1.35-dev)
• Apache HTTP Server (apache2)
• Xerces C++ parser (libxerces-c28)
• Xerces development files (libxerces-c2-dev)
• SSL development libraries (libssl-dev)
• SQLite 3 development files (libsqlite3-dev)
• Simple JSON for Python (python-simplejson)

Note, this is with respect to the Console, not the node - you may need to install additional packages before NOX can be installed properly.

If all dependencies are taken care of, NOX will install with the following steps.

git clone git://noxrepo.org/noxcore
cd noxcore/
./boot.sh
mkdir build/
cd build/
../configure --with-python=yes
make
make check 

Controllers on the Console

A sub-set of these instructions can be used to install a "custom" controller in userspace on the console. Most of the requisite libraries should already be installed. Use the following commands to install the Reference system in your userspace:

for the OpenFlow Reference System :

cd
git clone http://openflowswitch.org/openflow
cd openflow
./boot.sh
./configure --with-l26=/lib/modules/`uname -r`/build
make
make install

for NOX :

cd
git clone git://noxrepo.org/noxcore
cd noxcore/
./boot.sh
mkdir build/
cd build/
../configure --with-python=yes
make
make check 

Starting the controller

Both commands start the controller and establish a connection with the OpenFlow switch. The -v is for verbose. -h for both will give you the help files for the controllers. In the reference system, the controller is found under …/openflow/controller/

./controller -v ptcp:6633 

and in NOX, it is found under …/noxcore/build/src/

./nox-core -v -i ptcp:6633 

ptcp:6633 refers to a passive connection to TCP 6633, the default OpenFlow port. An active connection method using standard TCP exists, however this does not work on this setup. In the OpenFlow reference system, a log of the verbose output can be saved by appending --log-file [filename].

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Available Tools

Some of these tools require root privileges and will thus require a custom installation on a node. Others can be run from the console directly in an unprivileged mode.

the Wireshark plugin

The OpenFlow Reference system comes with an OpenFlow wireshark dissector.

Permissions:
You must be root in order to use Wireshark; Therefore you must install it on a node.

Prerequisites:
glib (and of course, wireshark) is required for the plugin to work:

apt-get install wireshark libgtk2.0-dev

Installation:
The patch is located under the utilities directory:

cd utilities/wireshark_dissectors/openflow
make
sudo make install

Usage:
To use wireshark, you need to do some X11 tunneling. To do this, add the -X option when using SSH to access the Console and the nodes.

tcpdump pcap files can also be opened using wireshark - once the plugin has been installed, OpenFlow packets can be interpreted from these files as well.

Iperf

For performance testing, you may want to run some bandwidth tests. iperf is a tool that measures maximum network performance using TCP for throughput and UDP for jitter and datagram loss. The standard image used for the Sandbox nodes when booted with command omf tell on comes with iperf. To take measurements, you need at least two nodes. One node becomes the server, the other(s), clients.

Permissions:
Iperf does not require root access.

Usage:
Initially, eth0 (the OpenFlow interface for the nodes) will be disabled. Additionally, there is no DHCP service on that VLAN - you need to enable the interface and statically set the IP address (i.e. using ifconfig). 192.168.x.y is the block associated with the OpenFlow VLAN.

To start the server:

iperf -s 

and on the client:

iperf -c 192.168.x.y 

Where 192.168.x.y is the IP address of the iperf server. A caveat is that iperf cannot take real-time bandwidth measurements. Real-time bandwidth use can be monitored using BWM-ng.

On the Console
Iperf is also installed on the Console. The interfaces available on the Console are the following:

• eth1 - 192.168.100.28
• eth1.27 / Control - 10.19.0.10
• eth1.28 / OF virtual switch - 192.168.1.28
• eth1.100 / OFP interface - 172.16.100.1

BWM-ng

BWM-ng is a tool capable of taking real-time throughput measurements of different interfaces of a host.

Permissions:
BWM-ng does not require root access, and is installed on the Console.

Usage:
By default, the tool will monitor all interfaces on the Console. To monitor just the OpenFlow interface, you must specify eth1.100. To output this to a csv, use the following command:

bwm-ng -I eth1.100 -o csv -t 1000 -F <file-name>

• -I : interface
• -o : output, either in csv or html
• -t : specifies sampling rate in msec. Here, it is 1000 msec, or 1 sample/sec
• -F : Filename of output

Installation on a node
The following command will install BWM-ng:

apt-get install bwm-ng

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Development

The files defining OpenFlow Protocol can be found in the following locations:

• OpenFlow reference system: openflow/include/openflow/openflow.h
• NOX: noxcore/src/include/openflow.hh

In addition, NOX provides a ​Web API that allows you to do development in C++ or Python.