from mininet.net import Mininet
from mininet.topo import Topo
from mininet.cli import CLI

class TreeTopology(Topo):
    def __init__(self):
        Topo.__init__(self)

        core_switch = self.addSwitch('core', dpid='000000000001')
        
        aggregation_switches = []
        edge_switches = []

        for i in range(2):
            agg_switch = self.addSwitch('a_s%d' % (i + 1), dpid=format(i + 2, '016x'))
            self.addLink(core_switch, agg_switch)
            aggregation_switches.append(agg_switch)

            for j in range(2):
                edge_switch = self.addSwitch('e_s%d' % (i * 2 + j + 1), dpid=format(i * 2 + j + 3, '016x'))
                self.addLink(agg_switch, edge_switch)
                edge_switches.append(edge_switch)

                for k in range(2):
                    host = self.addHost('h%d' % (i * 4 + j * 2 + k + 1))
                    self.addLink(edge_switch, host)

topo = TreeTopology()
net = Mininet(topo)
net.start()

CLI(net)

net.stop()