In band controller

SDN Can be deployed in two ways..

Out Band Control : All the switches are directly connected to controller. So controller traffic go via the directly connected links.

s1 ---  s2 --- s3
 l         l       l
 l ----- c1----- l

In Band Control : A switch is connected to the controller via another switch

s1 --- s2
 l
c1


#!/usr/bin/python

from mininet.net import Mininet
from mininet.node import RemoteController, OVSSwitch
from mininet.cli import CLI
from mininet.log import setLogLevel, info

class InbandController( RemoteController ):

    def checkListening( self ):
        "Overridden to do nothing."
        return

def emptyNet():

    "Create an empty network and add nodes to it."

    net = Mininet( topo=None, build=False)

    net.addController('c0', controller=InbandController, ip='10.0.0.1')

    h1 = net.addHost( 'h1', ip='10.0.0.1' )
    h2 = net.addHost( 'h2', ip='10.0.0.2' )
    h3 = net.addHost( 'h3', ip='10.0.0.3' )

    s1 = net.addSwitch( 's1', cls=OVSSwitch )

    net.addLink( h1, s1 )
    net.addLink( h2, s1 )
    net.addLink( h3, s1 )

    net.start()
    s1.cmd('ifconfig s1 10.0.0.10')

    CLI( net )
    net.stop()

if __name__ == '__main__':
    setLogLevel( 'info' )
    emptyNet()

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We start the controller in h1..

So start the controller.  First open an xterm to h1, which is where we said the controller would be.

mininet> xterm h1

When the xterm opens, start the controller. For this quick test, we will just start the OpenFlow Reference controller.

root@mininet-vm:~# controller -v ptcp:6633

This means that the controller and switch are successfully talking to each other.  And if you do a pingall now.

mininet> pingall
*** Ping: testing ping reachability
h1 -> h2 h3
h2 -> h1 h3
h3 -> h1 h2
*** Results: 0% dropped (6/6 received)