=== Simple Mininet topology

[source,python]
----
!/usr/bin/python

from mininet.topo import Topo

class SimpleTopology( Topo ):
    "Simple topology example."

    def __init__( self ):
        "Create custom topo."

        # <1>
	Topo.__init__( self )

        # <2>
        Switch1 = self.addSwitch( 's1' )
        Switch2 = self.addSwitch( 's2' )
        Switch3 = self.addSwitch( 's3' )
        Switch4 = self.addSwitch( 's4' )
        Host11 = self.addHost( 'h1' )
        Host12 = self.addHost( 'h2' )
        Host21 = self.addHost( 'h3' )
        Host22 = self.addHost( 'h4' )
        Host23 = self.addHost( 'h5' )
        Service1 = self.addHost( 'srvc1' ) # <3>

	# <4>
        self.addLink( Host11, Switch1 )
        self.addLink( Host12, Switch1 )
        self.addLink( Host21, Switch2 )
        self.addLink( Host22, Switch2 )
        self.addLink( Host23, Switch2 )
        self.addLink( Switch1, Switch2 )
        self.addLink( Switch2, Switch4 )
        self.addLink( Switch4, Switch3 )
        self.addLink( Switch3, Switch1 )
        self.addLink( Switch3, Service1 )
        self.addLink( Switch4, Service1 )


topos = { 'simpletopology': ( lambda: SimpleTopology() ) }
----
<1> Initialize topology
<2> Add hosts and switches
<3> Host used to represent the service
<4> Add links

[quote]
Source: https://gist.github.com/vinothgithub15/315d0a427d5afc39f2d7