tmp

from mininet.topo import Topo
from mininet.net import Mininet
from mininet.node import OVSController
from mininet.link import TCLink
from mininet.cli import CLI
from mininet.log import setLogLevel

class CustomTopo(Topo):
    def build(self):
        h1 = self.addHost('h1')
        h2 = self.addHost('h2')
        h3 = self.addHost('h3')
        h4 = self.addHost('h4')

        s1 = self.addSwitch('s1')
        s2 = self.addSwitch('s2')
        s3 = self.addSwitch('s3')

        self.addLink(s1, s2, bw=15)
        self.addLink(s2, s3, bw=15)
        self.addLink(s1, h1)
        self.addLink(s2, h2)
        self.addLink(s3, h3)
        self.addLink(s3, h4)

def runIperf(net):
    h1, h2, h3, h4 = net.get('h1', 'h2', 'h3', 'h4')

    h3.cmd('iperf3 -s -D')
    h4.cmd('iperf3 -s -D')

    print("Testing TCP bandwidth between h1 and h3")
    net.iperf((h1, h3))

    print("Testing TCP bandwidth between h2 and h4")
    net.iperf((h2, h4))

if __name__ == '__main__':
    setLogLevel('info')

    topo = CustomTopo()
    net = Mininet(topo=topo, controller=OVSController, link=TCLink)
    net.start()

    runIperf(net)

    CLI(net)

    net.stop()