A simple mininet topology

Topo.py

from mininet.topo import Topo
from mininet.link import TCLink
from mininet.log import info
from mininet.net import Mininet
from mininet.cli import CLI
from mininet.node import RemoteController


def main():
    net = Mininet(link=TCLink)

    controller = RemoteController("c1")

    info("*** Adding Switches ***\n")
    s1 = net.addSwitch("s1")
    s2 = net.addSwitch("s2")
    s3 = net.addSwitch("s3")
    s4 = net.addSwitch("s4")

    info("*** Adding Hosts ***\n")
    h1 = net.addHost("h1")
    h2 = net.addHost("h2")

    info("*** Adding Links ***\n")
    net.addLink(s1, h1)
    net.addLink(s4, h2)
    net.addLink(s1, s2, delay="10ms", bw=10)
    net.addLink(s1, s3, delay="20ms", bw=10)
    net.addLink(s4, s2)
    net.addLink(s4, s3)

    info("*** Starting network ***\n")
    net.build()

    s1.start([controller])
    s2.start([controller])
    s3.start([controller])
    s4.start([controller])

    info("*** Running CLI ***\n")
    CLI(net).run()

    info("*** Stopping network ***\n")
    net.stop()


if __name__ == '__main__':
    main()