OpenFlow Switch on Raspberry Pi Part 3: Configuration and getting it running

In part 1 I showed what hardware you need to turn your Raspberry Pi into an OpenFlow switch by  adding USB to Ethernet adaptors.

In part 2 I showed how to install Erlang and install the LINC OpenFlow switch

In this part we start with configuring the switch.

The first thing we need to do is identify what networking ports we have on our Pi.

We use the command ifconfig -a to find out what Ethernet ports we have

pi@raspberrypi ~ $ ifconfig -a

eth0      Link encap:Ethernet  HWaddr b8:27:eb:21:08:6a
          inet addr:192.168.1.19  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:121 errors:0 dropped:0 overruns:0 frame:0
          TX packets:83 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:11559 (11.2 KiB)  TX bytes:11040 (10.7 KiB)

eth1      Link encap:Ethernet  HWaddr 00:e0:4c:53:44:58
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0  carrier:0  
          collisions:0  txqueuelen:1000                                                                               
           RX bytes:0 (0.0 B)  TX bytes:0 (0.0B)   

eth2      Link encap:Ethernet  HWaddr 00:e0:4c:53:44:58
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlan0     Link encap:Ethernet  HWaddr 00:0b:81:89:5e:bf
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)


Port eth0 is the native Ethernet port on the Pi and the USB based Ethernet ports are showing up as eth1, eth2 and wlan0.  If you've added more or different ports for your hardware, your port numbers will differ.

We now need to edit the LINC config file so that it knows what ports it has access to.
If the version you have downloaded is higher than 1.0 you'll need to change the line below

pi@raspberrypi ~/LINC-Switch $ sudo vi rel/linc/releases/1.0/sys.config

We now need to edit the section of the file to declare the ports which form part of the switch

       {ports,
        [
         %% - regular hardware interface
         {port, 1, [{interface, "eth1"}]},
         {port, 2, [{interface, "eth2"}]},
         {port, 3, [{interface, "wlan0"}]},
         {port, 4, [{interface, "eth0"}]}
         %% - hardware interface with explicit type
         %% {port, 1, [{interface, "net0"}, {type, eth}]},
         %% - regular tap interface
         %% {port, 2, [{interface, "tap0"}]},
         %% - tap interface under MacOSX with dynamically assigned IP
         %% {port, 3, [{interface, "tap1"}, {ip, "10.0.0.1"}]},
         %% - tap interface with explicit type
         %% {port, 4, [{interface, "net1"}, {type, tap}]}
        ]},

Note that the last active port shouldn't have a comma after it

We can now start the OpenFlow switch for the first time

pi@raspberrypi ~/LINC-Switch $ sudo rel/linc/bin/linc console

Exec: /home/pi/LINC-Switch/rel/linc/erts-5.9.3.1/bin/erlexec -boot /home/pi/LINC-Switch/rel/linc/releases/1.0/linc -mode embedded -config /home/pi/LINC-Switch/rel/linc/releases/1.0/sys.config -args_file /home/pi/LINC-Switch/rel/linc/releases/1.0/vm.args -- console
Root: /home/pi/LINC-Switch/rel/linc
Erlang R15B03 (erts-5.9.3.1) [source] [async-threads:0] [kernel-poll:false]

21:18:47.473 [info] Application lager started on node linc@raspberrypi
21:18:47.483 [info] Application ssh started on node linc@raspberrypi
21:18:47.542 [info] Application enetconf started on node linc@raspberrypi
21:18:47.557 [info] Application linc started on node linc@raspberrypi
Eshell V5.9.3.1  (abort with ^G)
(linc@raspberrypi)1> 21:18:47.957 [info] Created port: {port,4,[{queues_status,disabled},{queues,[]},{config,{port_configuration,undefined,up,false,false,false}},{features,{features,undefined,'100Mb-FD',true,copper,unsupported}},{interface,"eth0"}]}
21:18:48.197 [info] Created port: {port,3,[{queues_status,disabled},{queues,[]},{config,{port_configuration,undefined,up,false,false,false}},{features,{features,undefined,'100Mb-FD',true,copper,unsupported}},{queues,[]},{interface,"wlan0"}]}
21:18:48.435 [info] Created port: {port,2,[{queues_status,disabled},{queues,[]},{config,{port_configuration,undefined,up,false,false,false}},{features,{features,undefined,'100Mb-FD',true,copper,unsupported}},{queues,[]},{interface,"eth2"}]}
21:18:48.704 [info] Created port: {port,1,[{queues_status,disabled},{queues,[]},{config,{port_configuration,undefined,up,false,false,false}},{features,{features,undefined,'100Mb-FD',true,copper,unsupported}},{queues,[]},{interface,"eth1"}]}

(linc@raspberrypi)1>
You can see LINC has created the ports defined in the config file and ended with the Erlang prompt.

OK. Let's shutdown the switch. We use the Erlang command  init:stop().

(linc@raspberrypi)1> init:stop().
ok

In the next post we'll get an OpenFlow controller running and start talking to the switch.