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

class TreeTopology(Topo):
    def build(self, n=2):
        core_switch = self.addSwitch('s1')

        switch_count = 0
        host_count = 0

        for _ in range(n):
            agg_switch = self.addSwitch('a_s%d' % (switch_count + 1))
            self.addLink(core_switch, agg_switch)

            switch_count += 1

            for _ in range(n):
                edge_switch = self.addSwitch('e_s%d' % (switch_count + 1))
                self.addLink(agg_switch, edge_switch)

                switch_count += 1

                for _ in range(n):
                    host = self.addHost('h%d' % (host_count + 1))
                    self.addLink(edge_switch, host)

                    host_count += 1

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

CLI(net)

net.stop()