delay_topo.py

"""Custom topology example

Two directly connected switches plus a host for each switch:

   host --- switch --- switch --- host

Adding the 'topos' dict with a key/value pair to generate our newly defined
topology enables one to pass in '--topo=mytopo' from the command line.
"""

from mininet.topo import Topo
from mininet.link import TCLink

class MyTopo( Topo ):
    "Simple topology example."

    def __init__( self ):
        "Create custom topo."

        # Initialize topology
        Topo.__init__( self )

        # Add hosts and switches
        host1 = self.addHost( 'h1' )
        host2 = self.addHost( 'h2' )
        switch1 = self.addSwitch( 's1' )
        switch2 = self.addSwitch( 's2' )
	switch3 = self.addSwitch( 's3' )

        # Add links
        self.addLink( host1, switch1 )
	self.addLink( switch1, switch2, delay='2ms' )
        self.addLink( switch2, switch3, delay='3ms' )
        self.addLink( switch3, host2 )


topos = { 'mytopo': ( lambda: MyTopo() ) }