Shanto Roy

I Explore Research, Tech, Travel, and Business. PhD Student @UHCS.

5 minute read

Earlier, in a tutorial, I have discussed how to configure a Raspberry Pi as a Open Flow Switch. In this tutorial, I will show some basic bridge configuration in a Raspberry Pi open flow switch.

How to Configure a Raspberry Pi as an OpenFlow Switch: Steps, Issues, and Solutions

Open Flow Switch

OpenFlow is a communication protocol used to manage traffic between routers and switches in a Software-Defined Network (SDN). OpenFlow-based switches are the core of any SDN. In this tutorial, we’ll explore the basics of configuring a bridge using an OpenFlow switch.

An OpenFlow switch is a network device that uses the OpenFlow protocol to communicate with an OpenFlow controller. The controller provides the switch with a set of rules for forwarding packets, and the switch then follows those rules to make forwarding decisions.

OpenFlow switches allow network administrators to centralize network management and control traffic flows more dynamically.

Bridge Configurations

  1. Configure Open vSwitch by creating a bridge using the following command:

    $ sudo ovs-vsctl add-br bridge_name

    Replace “bridge_name” with the name you want to give your bridge.

  2. Add your Raspberry Pi’s Ethernet interface to the bridge using the following command:

    $ sudo ovs-vsctl add-port bridge_name eth0

    Replace “bridge_name” with the name of your bridge and “eth0” with the name of your Ethernet interface.

  3. To display the OpenFlow ports for the bridge, you can run the following command:

     $ sudo ovs-ofctl show bridge_name

    This command will output the OpenFlow ports for each physical port on the bridge, along with the port number assigned by OpenFlow. You can then use these port numbers in your OpenFlow rules.

  4. Configure the IP address of your Raspberry Pi’s bridge interface:

    $ sudo ifconfig bridge_name <IP_address> netmask <subnet_mask>

    Replace “bridge_name” with the name of your bridge, and “" and "" with your desired IP address and subnet mask.

    or create a virtual interface using the following command

    $ sudo ip addr add 192.168.1.1/24 dev mybridge
  5. Test your Open vSwitch configuration by pinging a device on your network from your Raspberry Pi.

  6. Assign a name to the port that connects the two Raspberry Pi’s. You can use the following command to assign a name to the port:

    $ sudo ovs-vsctl set interface <port_name> ofport_request=<port_number>

    Replace “" with a name you want to assign to the port, and "" with a unique port number you want to assign to the port.

  7. To deactivate the port, you can use the following command:

    $ sudo ovs-ofctl mod-port bridge_name <port_name> down

    Replace “bridge_name” with the name of the bridge that the port is attached to, and “" with the name you assigned to the port in step 1.

  8. To reactivate the port, you can use the following command:

    $ sudo ovs-ofctl mod-port bridge_name <port_name> up

Adding Flow Rules

  1. We can use the ovs-ofctl command to add flow rules to the switch. The syntax for the command is as follows:

    $ sudo ovs-ofctl add-flow <bridge> <flow>

    Where <bridge> is the name of the OpenFlow switch, and <flow> is the flow rule that you want to add.

    Here is an example of a flow rule that forwards all incoming packets to port 2:

    $ sudo ovs-ofctl add-flow br0 in_port=1,actions=output:2

    This command adds a flow rule to the switch br0 that matches incoming packets on port 1 and forwards them to port 2.

  2. We can also use the ovs-appctl command to view the current flow rules on the switch:

    $ sudo ovs-appctl ofproto/trace <bridge> <flow>

    Where <bridge> is the name of the OpenFlow switch, and <flow> is the flow rule that you want to trace. This command will display the flow of the packet through the switch and show which flow rules match the packet.

Troubleshooting- Check if a link is Active

You can check if an Ethernet cable is connected to one of the Ethernet ports on your Raspberry Pi using the ethtool command. Here’s how you can do it:

  1. Install ethtool if it’s not already installed on your Raspberry Pi. You can use the following command to install it:

    $ sudo apt-get install ethtool

  2. Run the following command to check the link status of the Ethernet port:

    $ sudo ethtool eth0

    Replace “eth0” with the name of the Ethernet interface that you want to check.

    The output of the command will show you the link status of the Ethernet port. If the cable is connected, the link status will be “Link detected: yes”. If the cable is not connected, the link status will be “Link detected: no”.

    Here’s an example output of the command with a connected Ethernet cable:

        Settings for eth0:
            Supported ports: [ TP ]
            Supported link modes:   10baseT/Half 10baseT/Full
                                    100baseT/Half 100baseT/Full
            Supported pause frame use: No
            Supports auto-negotiation: Yes
            Advertised link modes:  10baseT/Half 10baseT/Full
                                    100baseT/Half 100baseT/Full
            Advertised pause frame use: Symmetric
            Advertised auto-negotiation: Yes
            Speed: 100Mb/s
            Duplex: Full
            Port: Twisted Pair
            PHYAD: 1
            Transceiver: internal
            Auto-negotiation: on
            MDI-X: off (auto)
            Supports Wake-on: pumbg
            Wake-on: d
            Current message level: 0x00000007 (7)
                                   drv probe link
            Link detected: yes  <-- Cable is connected

    Here’s an example output of the command with a disconnected Ethernet cable:

    Settings for eth0:
        Link detected: no  <-- Cable is not connected

That’s all for today!!!

Raspberry Pi

You can also read my other posts related to Raspberry Pi:

Full ARM Exploitation Series

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