SDN-Lab-2

Attribution: This lab uses OpenDaylight (Karaf distribution) and Mininet. OpenDaylight is licensed under the Eclipse Public License (EPL). Mininet is distributed under its respective license. This repository contains lab instructions and scripts for educational use.

Continue with what we had on previous lab, we will install OpenDaylight as the SDN controller to connect with Mininet to read the network statistics.

Learning Objectives

By the end of this lab, students will be able to:

• Deploy an SDN testbed by installing and launching OpenDaylight and connecting a Mininet topology using OpenFlow 1.3.

• Verify controller–switch connectivity by checking listening ports (e.g., 6653 for OpenFlow and 8181 for RESTCONF) and interpreting Mininet connection messages.

• Enable required OpenDaylight features (OpenFlow plugin, topology discovery, table-miss enforcer, REST services) and explain why a controller may appear “running” but not accept OpenFlow connections until plugins are installed.

• Capture and identify OpenFlow control traffic (e.g., HELLO/FEATURES requests, PACKET_IN/PACKET_OUT) using Wireshark and select the correct interface/namespace to monitor.

• Query OpenDaylight northbound APIs to retrieve network state (nodes, topology, flows) and interpret JSON responses using tools like jq.

• Distinguish OpenDaylight data stores by comparing config vs operational (non-config) flow state, and explain why flow entries may appear in one but not the other.

• Reason about SDN control-plane workflow: how southbound events (switch connect, discovery, packet-in) propagate into controller state and become visible through northbound APIs.

Virtual Machine Summary

Memory: >= 8GB

Storage: 50GB

CPU: 2 cores, AMD64 Architecture

Installation Disc: ubuntu-22.04.4-desktop-amd64.iso

References

An Instant Virtual Network on your Laptop (or other PC)

PICOS 4.4.3 Configuration G

OpenDaylight Flow Examples

Build a complete SDN testbed

1. Install and Configure Java

   (1) Install Java

   sudo apt-get install openjdk-17-jdk
   

   (2) Configure JAVA_HOME to /etc/profile

   sudo vim /etc/profile
   

   (3) Add the following to the end of /etc/profile

   JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
   PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
   export JAVA_HOME
   export JRE_HOME
   export PATH
   

   (4) Make JAVE_HOME valid and Test JAVA Version

   source /etc/profile
   java -version
   

2. Install OpenDaylight

   (1) Download OpenDaylight Calcium

   wget https://nexus.opendaylight.org/content/repositories/opendaylight.release/org/opendaylight/integration/karaf/0.20.1/karaf-0.20.1.zip
   

   (2) Extract it to $HOME

   unzip karaf-0.20.1.zip
   

   (3) Configure ODL-0.20.1 Environment

   cd karaf-0.20.1/bin
   vim setenv
   

   (4) Add the following to the setenv file

   export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
   

3. Run OpenDaylight. In a system terminal:

   sudo ./karaf
   

4. Connect Mininet to OpenDaylight

   (1) Run Mininet with Customized Topology and Connect to Controller

   sudo mn --custom ~/custom_mn/topo-2sw-2host.py --topo mytopo --switch ovsk,protocols=OpenFlow13 --controller remote,ip=127.0.0.1,port=6653
   

   NOTE: We can also have a remote controller building in another VM. If so, we connect Mininet to the remote controller with the $IP_ODL of that VM. The $IP_ODL can be known with the command ifconfig on the OpenDaylight VM.

   Question: Is the connection successful?

   If the connection between ODL and mininet is successful, the mininet terminal shows:

   *** Creating network
   *** Adding controller
   *** Adding hosts:
   ...
   

   Otherwise, there will be Unable to connect the remote controller at $IP_ODL after *** Adding controller How to debug?

   (2) Check Listening Ports. Open another terminal

   sudo lsof -i -P -n | grep LISTEN
   

   Question: What do you observe?

   (3) Install OpenFlow Plugins in OpenDaylight terminal opendaylight-user@root>:

   feature:install odl-openflowplugin-app-topology-lldp-discovery odl-openflowplugin-app-table-miss-enforcer odl-openflowplugin-flow-services odl-openflowplugin-flow-services-rest odl-openflowplugin-app-topology-manager odl-openflowplugin-app-lldp-speaker
   

   (4) Check Listening Ports again.

   sudo lsof -i -P -n | grep LISTEN
   

   NOTE: If tcp *:6653 (LISTEN) and tcp *:8181 (LISTEN) do not show, shut down OpenDaylight with Control+D and restart sudo ./karaf

   (5) Re-run Mininet:

   sudo mn --custom ~/custom_mn/topo-2sw-2host.py --topo mytopo --switch ovsk,protocols=OpenFlow13 --controller remote,ip=127.0.0.1,port=6653
   

   Question: Is the connection successful this time?

5. Capture OpenFlow messages

   sudo wireshark
   

   Question: Which interface do we monitor?

6. Read network statistics from the northbound API of OpenDaylight

   (1) Create data folder. In a terminal,

   mkdir data
   

   (2) Request nodes (switches)

   Refer to req_nodes.sh

   Read nodes file:

   sudo vim data/nodes.sh
   

   In vim, press Ctrl+:, then type %!jq . for better json file reading.

   (3) Request topology

   Refer to odl/req_topo.sh

   Read topology file

7. Config Data Store & Nonconfig Data Store

   (1) Request the data store of a switch

   Refer to odl/req_flows.sh, we will need to figure out what to put as a variable following ./req_flows.sh.

   Question: What value do we put as the variable?

   Read the flows.json file, keep in mind what you see.

   (2) Request the nonconfig data store of a switch

   Refer to odl/req_nonconfig_flows.sh

   Read the nonconfig_flows.json file, keep in mind what you see.

   (3) Request the config data store of the same switch

   Refer to odl/req_config_flows.sh

   Read the config_flows.json file, keep in mind what you see.

   Question: Why?

   (4) Configure a flow entry on the mininet end, repeat (1)(2)(3) steps, reason about the config data store & nonconfig data store design of OpenDaylight.