Table of Contents
Mininet
This page documents the usage/installation of mininet as well as it's interaction with OEDL. The main source is the mininet homepage located at http://mininet.org/.
0. Installation
While mininet can be installed via an apt-package, the version that is in the repository is very old and does not have some important features so we will instead install by source. References can be found here
- Install build perquisite packages:
apt-get install build-essential git-core
- Clone the Repository:
git clone git://github.com/mininet/mininet
- According to the note located here, the default install comes with more packages than we need, so instead we will call the install script with the -nv flag
mininet/util/install.sh -nv
This will install the base mini-net dependencies with only open-vswitch support. Once installed you can try the pingall test to ensure the installation succeeded:
root@node1-1:~# sudo mn --test pingall *** Creating network *** Adding controller *** Adding hosts: h1 h2 *** Adding switches: s1 *** Adding links: (h1, s1) (h2, s1) *** Configuring hosts h1 h2 *** Starting controller c0 *** Starting 1 switches s1 *** Waiting for switches to connect s1 *** Ping: testing ping reachability h1 -> h2 h2 -> h1 *** Results: 0% dropped (2/2 received) *** Stopping 1 controllers c0 *** Stopping 1 switches s1 .. *** Stopping 2 links *** Stopping 2 hosts h1 h2 *** Done completed in 0.976 seconds
Example Usage
Mininet Cluster Edition
Mininet supports running a network across a set of nodes (cluster). Currently, this relies on SSH tunnels, and is experimental. To enable cluster support, on each node that will be part of the cluster:
- Generate and exchange SSH keys. If we are running a tiny cluster of node1-1 and node1-2:
ssh-keygen -t rsa ssh-copy-id root@node1-1 ssh-copy-id root@node1-2
Note how a node also has to have its own key in authorized_keys, so we runssh-copy-idagainst every node in the cluster.
- Edit /etc/ssh/sshd_config, adding the following two lines:
AllowTCPForwarding yes PermitTunnel yes
- restart
sshdservice ssh restart
If all goes well, you should be able to run the following to run a tree topology across nodes1-1 and node1-2:
# mn --cluster node1-1,node1-2 --topo tree,2,3
The virtual switches are distributed randomly across the two nodes, as indicated as part of the above command's output:
*** Placing nodes h1:node1-1 h2:node1-1 h3:node1-1 h4:node1-2 h5:node1-2 h6:node1-2 h7:node1-2 h8:node1-2 h9:node1-2 s1: node1-1 s2:node1-1 s3:node1-2 s4:node1-2
If you have a controller running remotely, you can append the —controller remote,ip=x.x.x.x argument like in a regular mn command.
1.2.1 Using Wireshark
In the above example, tcpdump can be replaced by wireshark. Wireshark is "friendlier" in that it has a GUI and an OpenFlow dissector plugin is available for it. In order to use Wireshark, you must enable X11 forwarding from your workstation to the node, with the -X or -Y flag for ssh e.g.:
ssh -X -l root node1-1
1.2.2 Using OpenVswitch directly
Mininet's datapaths are backed by OVS. Therefore, if you have a Mininet install, you get OVS for "free". You can use OVS directly for your data plane.
II More complex examples
It is possible to run multiple instances of controllers (for whatever reason), or different logical components together in the same network. This section shows two examples of more complex SDN network setups - multiple controller instances and with FlowVisor, a network hypervisor.
2.1 Multiple Controllers
You may have multiple controllers in the same logical space of the control plane for various reasons - special applications, fail-over, distributed control planes, etc.
- 2.1.1 On multiple hosts
- 2.1.2 On the same host
2.1.1 On multiple hosts If each controller is running on its own host (machine, VM, etc.), there is little to change; if you have hosts A,B, and C, and Floodlight instances running on each, switches can be pointed to targets A:6633, B:6633, C:6633, or any combination thereof (switches can be pointed to multiple controllers).
2.1.2 On the same host #s2_1_2
The Floodlight configuration file Multiple instances of Floodlight may be run on the same host, as long as each controller listens on a separate set of sockets. In this case, all controllers would be on the same IP address(es), so you must change the ports they are listening on. These ports include the OpenFlow control port (TCP 6633), REST API (TCP 8080), and debug (TCP 6655).
In Floodlight, this value can be changed by modifying the file floodlightdefault.properties, located in src/main/resources/ of the Floodlight sources. (Currently) It looks like this:
floodlight.modules=\ net.floodlightcontroller.jython.JythonDebugInterface,\ net.floodlightcontroller.counter.CounterStore,\ net.floodlightcontroller.storage.memory.MemoryStorageSource,\ net.floodlightcontroller.core.internal.FloodlightProvider,\ net.floodlightcontroller.threadpool.ThreadPool,\ net.floodlightcontroller.devicemanager.internal.DeviceManagerImpl,\ net.floodlightcontroller.devicemanager.internal.DefaultEntityClassifier,\ net.floodlightcontroller.staticflowentry.StaticFlowEntryPusher,\ net.floodlightcontroller.firewall.Firewall,\ net.floodlightcontroller.forwarding.Forwarding,\ net.floodlightcontroller.linkdiscovery.internal.LinkDiscoveryManager,\ net.floodlightcontroller.topology.TopologyManager,\ net.floodlightcontroller.flowcache.FlowReconcileManager,\ net.floodlightcontroller.debugcounter.DebugCounter,\ net.floodlightcontroller.debugevent.DebugEvent,\ net.floodlightcontroller.perfmon.PktInProcessingTime,\ net.floodlightcontroller.ui.web.StaticWebRoutable,\ net.floodlightcontroller.loadbalancer.LoadBalancer,\ org.sdnplatform.sync.internal.SyncManager,\ org.sdnplatform.sync.internal.SyncTorture,\ net.floodlightcontroller.devicemanager.internal.DefaultEntityClassifier org.sdnplatform.sync.internal.SyncManager.authScheme=CHALLENGE_RESPONSE org.sdnplatform.sync.internal.SyncManager.keyStorePath=/etc/floodlight/auth_credentials.jceks org.sdnplatform.sync.internal.SyncManager.dbPath=/var/lib/floodlight/
Several entries can be added to this list to tweak TCP port values. Unfortunately, these entries may change fairly frequently due to active development.
- net.floodlightcontroller.restserver.RestApiServer.port = 8080
- net.floodlightcontroller.core.internal.FloodlightProvider.openflowport = 6633
- net.floodlightcontroller.jython.JythonDebugInterface.port = 6655
Each entry should be on its own line, with no spaces or newlines in between lines. For example, to change the port that Floodlight listens for switches on from the default of 6633 to 6634, append:
net.floodlightcontroller.core.internal.FloodlightProvider.openflowport = 6634
To the .properties file. Then, point Floodlight to the configuration file with the -cf flag:
java -jar target/floodlight.jar -cf src/main/resources/floodlightdefault.properties
The file specified after -cf will be read in, and the values in it used to configure the controller instance. You should be able to confirm the change:
# netstat -nlp | grep 6634 ... tcp6 0 0 :::6634 :::* LISTEN 2029/java ...
Launching multiple controllers
Each instance of the controller run on the same host can be pointed to its own .properties file with the -cf flag, with different port value parameters. Begin by making as many copies of the default .properties file as you will have controllers. Going with a similar example as earlier, you can have one host A and three Floodlight instances 1,2, and 3, configured as below:
1 2 3 FloodlightProvider.openflowport 6633 6634 6635 RestApiServer.port 8080 8081 8082 JythonDebugInterface.port 6655 6656 6657
No ports should be shared by the three instances, or else they will probably throw errors at startup and exit shortly after. With a .properties file for each instance under resources/ (named 1,2, and 3.properties for this example), you can launch the controllers in a loop for example:
for i in `seq 1 3`; do java -jar target/floodlight.jar -cf src/main/resources/$i.properties 1>/dev/null 2>&1 & done
This should launch three backgrounded instances of Floodlight.
2.2 Network virtualization/slicing
A more typical case you might encounter is a network that is sliced, or virtualized.
- 2.2.1 A brief intro to network virtualization
- 2.2.2 Virtualization with multiple hosts
- 2.2.3 On the same host
2.2.1 A brief intro to network virtualization
A virtualized network is organized as below:
[controller 1] [controller 2] [controller 3]
\ | /
\ | /
[network hypervisor]-[policies]
|
[network]
A network hyperviser like FlowVisor sits between the control and data plane, intercepting and re-writing the contents of the OpenFlow control channel to one or more controllers running independently of one another. Ultimately, the network hypervisor provides each controller with an illusion that it is the only controller in the network. It accomplishes this by
- Rewriting the topology information conveyed by OpenFlow (in the form of PORT_STATs and PacketIns triggered by LLDP messages) before it reaches each controller, allowing it to only work on a subset, or slice, of the network, and
- Mapping the PacketIns/PacketOuts to and from each controller to the proper sets of switches and switch ports.
How the re-writing occurs depends on a set of admin-defined policies.
2.2.2 Virtualization with multiple hosts
We begin by introducing a simple example of a virtualized topology:
[Floodlight 1] [Floodlight 2]
\ /
[FlowVisor]
|
[Mininet]
Each component above will be run on a separate node. Since we need more than two nodes, you may want to reserve either Sandboxes 4 or 9. The components can also be run on the same node, with the caveats discussed in the next section, 2.2.3.
Here, Mininet will be used to emulate a three-switch, three-host data plane:
h1 h2 h3 | | | s1---s2---s3
This data plane will be sliced so that one Floodlight instance will control switches s1 and s2, and the other, s3.
2.2.3 On the same host
As with the case of multiple controllers on the same VM/host, you must be careful that neither FlowVisor nor the controllers listen on the same sets of ports. For the multiple controllers, this can be avoided as described in Section 2.1.2. FlowVisor and Floodlight conflict on ports 6633 and 8080.
3.3 Cbench
website: http://docs.projectfloodlight.org/display/floodlightcontroller/Cbench+(New)
dependencies
sudo apt-get install autoconf automake libtool libsnmp-dev libpcap-dev
installation/build
git clone git://gitosis.stanford.edu/openflow.git
cd openflow; git checkout -b mybranch origin/release/1.0.0
git clone git://gitosis.stanford.edu/oflops.git
git submodule init && git submodule update
wget http://hyperrealm.com/libconfig/libconfig-1.4.9.tar.gz
tar -xvzf libconfig-1.4.9.tar.gz
cd libconfig-1.4.9
./configure
sudo make && sudo make install
cd ../oflops/
sh ./boot.sh ; ./configure --with-openflow-src-dir=${OF_PATH}/openflow/
make install
Where OF_PATH is where you had cloned the OpenFlow repository to.
run
Run from the cbench directory under oflops:
cd cbench cbench -c localhost -p 6633 -m 10000 -l 10 -s 16 -M 1000 -t
- -c localhost : controller at loopback
- -p 6633 : controller listaning at port 6633
- -m 10000 : 10000 ms (10 sec) per test
- -l 10 : 10 loops(trials) per test
- -s 16 : 16 emulated switches
- -M 1000 : 1000 unique MAC addresses(hosts) per switch
- -t : throughput testing
for the complete list, use the -h flag.
The output for the above command looks like this:
cbench: controller benchmarking tool running in mode 'throughput' connecting to controller at localhost:6633 faking 16 switches offset 1 :: 3 tests each; 10000 ms per test with 10 unique source MACs per switch learning destination mac addresses before the test starting test with 0 ms delay after features_reply ignoring first 1 "warmup" and last 0 "cooldown" loops connection delay of 0ms per 1 switch(es) debugging info is off 16:53:14.384 16 switches: flows/sec: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 total = 0.028796 per ms 16:53:24.485 16 switches: flows/sec: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 total = 0.031999 per ms 16:53:34.590 16 switches: flows/sec: 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 total = 0.038380 per ms RESULT: 16 switches 2 tests min/max/avg/stdev = 32.00/38.38/35.19/3.19 responses/s
—-
3.4 liboftrace (ofdump/ofstats)
docs:
https://github.com/capveg/oftrace/blob/master/README
http://www.openflow.org/wk/index.php/Liboftrace
dependencies
sudo apt-get install libpcap-dev swig libssl-dev
installation/build
git clone git://github.com/capveg/oftrace.git
cd oftrace
./boot.sh
./configure --with-openflow-src-dir=${OF_PATH}/openflow/
make && make install
run
There are two tools pre-packaged with liboftrace (as per a mailing-list entry):
- ofstats: a program which calculates the controller processing delay, i.e., the difference in time between a packet_in message and the corresponding packet_out or flow_mod message.
- ofdump: a program that simply lists openflow message types with timestamps by switch/controller pair.
Both have the same syntax:
[ofstats|ofdump] [controller IP] [OF port]
Without the arguments it defaults to localhost:6633.
For example, with a pcap file named sample.pcap from a tcpdump session sniffing for traffic from a controller at 192.168.1.5, port 6637:
ofdump:
# ofdump sample.pcap 192.168.1.5 6637 DBG: tracking NEW stream : 192.168.1.5:6637-> 192.168.1.6:47598 DBG: tracking NEW stream : 192.168.1.6:47598-> 192.168.1.5:6637 FROM 192.168.1.5:6637 TO 192.168.1.6:47598 OFP_TYPE 0 LEN 8 TIME 0.000000 FROM 192.168.1.6:47598 TO 192.168.1.5:6637 OFP_TYPE 0 LEN 8 TIME 0.026077 FROM 192.168.1.5:6637 TO 192.168.1.6:47598 OFP_TYPE 5 LEN 8 TIME 0.029839 FROM 192.168.1.6:47598 TO 192.168.1.5:6637 OFP_TYPE 6 LEN 128 TIME 0.1070415 ... FROM 192.168.1.6:47598 TO 192.168.1.5:6637 OFP_TYPE 10 LEN 60 TIME 0.2038485 --- 2 sessions: 0 0 FROM 192.168.1.5:6637 TO 192.168.1.6:47598 OFP_TYPE 13 LEN 24 TIME 0.2038523 FROM 192.168.1.6:47598 TO 192.168.1.5:6637 OFP_TYPE 10 LEN 60 TIME 0.2038573 FROM 192.168.1.5:6637 TO 192.168.1.6:47598 OFP_TYPE 13 LEN 24 TIME 0.2038614 FROM 192.168.1.6:47598 TO 192.168.1.5:6637 OFP_TYPE 10 LEN 60 TIME 0.2038663 FROM 192.168.1.5:6637 TO 192.168.1.6:47598 OFP_TYPE 13 LEN 24 TIME 0.2038704 Total OpenFlow Messages: 20015
ofstats:
# ofstats sample.pcap 192.168.1.5 6637 Reading from pcap file 1.pcap for controller 192.168.1.5 on port 6637 DBG: tracking NEW stream : 192.168.1.5:6637-> 192.168.1.6:47598 DBG: tracking NEW stream : 192.168.1.6:47598-> 192.168.1.5:6637 0.008088 secs_to_resp buf_id=333 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 0 queued 0.000454 secs_to_resp buf_id=334 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 2 queued 0.000437 secs_to_resp buf_id=335 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 1 queued 0.000534 secs_to_resp buf_id=336 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 0 queued 0.000273 secs_to_resp buf_id=337 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 2 queued 0.000486 secs_to_resp buf_id=338 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 2 queued 0.000379 secs_to_resp buf_id=339 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 1 queued 0.000275 secs_to_resp buf_id=340 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 0 queued ... 0.000135 secs_to_resp buf_id=10330 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 1 queued 0.000132 secs_to_resp buf_id=10331 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 1 queued 0.000131 secs_to_resp buf_id=10332 in flow 192.168.1.5:6637 -> 192.168.1.6:47598 - packet_out - 0 queued
Since the outputs are dumped to stdout it is probably best to redirect it to a file for parsing later, like so:
# ofstats sample.pcap 192.168.1.5 6637 > outfile
3.5 Wireshark
website(wireshark): http://www.wireshark.org
docs(plugin): https://bitbucket.org/barnstorm/of-dissector
dependencies
wireshark(source):
sudo apt-get install libpcap-dev bison flex libgtk2.0-dev build-essential
plugin:
sudo apt-get install scons mercurial
installation/build
You need the source for Wireshark to build the plugin. At the time of this writing Wireshark is at v.1.10.
wget http://wiresharkdownloads.riverbed.com/wireshark/src/wireshark-1.10.0.tar.bz2 tar -xjf wireshark-1.10.0.tar.bz2 cd wireshark-1.10.0/ ./configure
The above is sufficient for the plugin. Installing Wireshark from source e.g. with make;make install can take a while, so you may choose to install the binary, i.e. do:
apt-get install wireshark
If you decide to build from source, also install libwiretap1.
Next fetch and build the plugin:
hg clone https://bitbucket.org/barnstorm/of-dissector
cd of-dissector/
export WIRESHARK=${WS_ROOT}/wireshark-1.10.0/
cd src
scons install
cp openflow.so /usr/lib/wireshark/libwireshark1/plugins/
Where ${WS_ROOT} is the directory you've untarred the Wireshark source to. The plugin directory may also differ depending on if you installed Wireshark from source or not - if you did, the path will be something similar to /usr/local/lib/wireshark/plugins/1.10.0/
run
Run Wireshark as root:
sudo wireshark
You should see openflow.so in the list of plugins if you go to Help > About Wireshark > plugins.
Refrences
Floodlight
- Tutorials and other information can be found at http://docs.projectfloodlight.org/display/floodlightcontroller/For+Developers
Mininet
- FAQs: https://github.com/mininet/mininet/wiki/FAQ
- Getting Started: http://mininet.org/download/ Getting Started
- Sample Workflow: http://mininet.org/sample-workflow/ Sample Workflow
- Walkthrough: http://mininet.org/walkthrough/
FlowVisor website: http://onlab.us/flowvisor.html
