NePA TesT: Community Network Emulator

class TorusTopo( Topo ):

    """2-D Torus topology

       WARNING: this topology has LOOPS and WILL NOT WORK

       with the default controller or any Ethernet bridge

       without STP turned on! It can be used with STP, e.g.:

       # mn --topo torus,3,3 --switch lxbr,stp=1 --test pingall"""

    def __init__( self, x, y, *args, **kwargs ):

        Topo.__init__( self, *args, **kwargs )

        if x < 3 or y < 3:

            raise Exception( 'Please use 3x3 or greater for compatibility '

                            'with Mininet 2.1.0' )

        hosts, switches, dpid = {}, {}, 0

        # Create and wire interior

        for i in range( 0, x ):

            for j in range( 0, y ):

                loc = '%dx%d' % ( i + 1, j + 1 )

                # dpid cannot be zero for OVS

                dpid = ( i + 1 ) * 256 + ( j + 1 )

                switch = switches[ i, j ] = self.addSwitch( 's' + loc, dpid='%016x' % dpid )

                host = hosts[ i, j ] = self.addHost( 'h' + loc )

                self.addLink( host, switch )

        # Connect switches

        for i in range( 0, x ):

            for j in range( 0, y ):

                sw1 = switches[ i, j ]

                sw2 = switches[ i, ( j + 1 ) % y ]

                sw3 = switches[ ( i + 1 ) % x, j ]

                self.addLink( sw1, sw2 )

                self.addLink( sw1, sw3 )