from mininet.topo import Topo

class CustomTopo( Topo ):
    def build( self ):
        # Hosts
        TL_host = self.addHost( 'h1' )
        BL_host = self.addHost( 'h2' )

        TR_host = self.addHost( 'h3' )
        BR_host = self.addHost( 'h4' )

        # Swtiches
        L_switch = self.addSwitch( 's1' )
        R_switch = self.addSwitch( 's2' )


        # Links
        self.addLink( TL_host, L_switch )
        self.addLink( BL_host, L_switch )

        self.addLink( TR_host, R_switch )
        self.addLink( BR_host, R_switch )

        self.addLink( L_switch, R_switch )


topos = { 'best-topo-eu': ( lambda: CustomTopo() ) }