Mininet Python - Issues With Pinging Other Hosts Within Custom Topology

Question

Info
Host OS: Windows 10
First Attempt Guest OS: Mininet-VM
Second Attempt Guest OS: Ubuntu(VM)
VM Software: Virtual Box

Libraries: Mininet Python API

Issue
Good day,

I'm having some issues with a my customized topology when using Mininet.

Initially, I used Mininet's recommended Mininet-VM and it works fine for the default command generated topologies(i.e.: linear, tree, reversed, etc).

However, when I wish to run my own topology I'm unable to ping any other host(see code below).

Commands:

1. "sudo python3 custom_topology.py
2. Mininet>pingall

I thought it might be an issue with the image of Mininet-VM itself and so I tried running the same script within Ubuntu(with Mininet installed of course) and ran into the same issue.

In any case, I've looked around stackoverflow(references below) and none of the solutions worked for me. Although, some have suggested to use the POX controller instead of the default one, but I'm quite ignorant on how it works as well as how to implement it.

Any help would be appreciated.

Cheers!

Result

Topology Diagram

Mid-Level API Code

from mininet.net import Mininet
from mininet.cli import CLI
from mininet.link import TCLink
from mininet.util import dumpNodeConnections
from mininet.node import Controller

net = Mininet(controller=Controller, link=TCLink)

h1 = net.addHost('h1')
h2 = net.addHost('h2')
h3 = net.addHost('h3')
h4 = net.addHost('h4')
h5 = net.addHost('h5')
h6 = net.addHost('h6')
h7 = net.addHost('h7')
h8 = net.addHost('h8')

s1 = net.addSwitch('s1')
s2 = net.addSwitch('s2')
s3 = net.addSwitch('s3')
s4 = net.addSwitch('s4')
s5 = net.addSwitch('s5')
s6 = net.addSwitch('s6')

c0 = net.addController('c0')

net.addLink(h1, s1)
net.addLink(h2, s2)
net.addLink(h3, s3)
net.addLink(h4, s4)
net.addLink(h5, s4)
net.addLink(h6, s5)
net.addLink(h7, s5)
net.addLink(h8, s6)

net.addLink(s1, s2, bw=10,  delay='0ms')
net.addLink(s2, s3, bw=10,  delay='0ms')
net.addLink(s3, s4, bw=100, delay='5ms')
net.addLink(s4, s5, bw=100, delay='5ms')
net.addLink(s5, s6, bw=100, delay='0ms')
net.addLink(s6, s1, bw=10,  delay='0ms')

net.start()
print( "Dumping host connections" )
dumpNodeConnections( net.hosts )
dumpNodeConnections( net.switches )
CLI(net)
net.stop()

References

1. StackOverflow Post 1
2. StackOverflow Post 2
3. StackOverflow Post 3
4. Official Mininet Website

Answer 1

Issue: The default controller within Mininet cannot handle loops within a topology. To fix this, we'll need to use the POX controller and some additional configuration for the switches.

You will need to run two terminals:

• one terminal will run POX controller as ./pox.py forwarding.hub
• the other terminal will run your custom topology python script

Please look at references #5 and #6, they display some decent examples

Code Solution

from mininet.net import Mininet
from mininet.node import Controller, RemoteController, 
OVSKernelSwitch, UserSwitch
from mininet.cli import CLI
from mininet.log import setLogLevel
from mininet.link import Link, TCLink


def topology():

  "Create a network."
  net = Mininet( controller=RemoteController, link=TCLink, 
  switch=OVSKernelSwitch )

  print("*** Creating nodes")
  h1 = net.addHost( 'h1', mac='00:00:00:00:00:01', ip='10.0.0.1/24' )
  h2 = net.addHost( 'h2', mac='00:00:00:00:00:02', ip='10.0.0.2/24' )
  h3 = net.addHost( 'h3', mac='00:00:00:00:00:03', ip='10.0.0.3/24' )
  h4 = net.addHost( 'h4', mac='00:00:00:00:00:04', ip='10.0.0.4/24' )
  h5 = net.addHost( 'h5', mac='00:00:00:00:00:05', ip='10.0.0.5/24' )
  h6 = net.addHost( 'h6', mac='00:00:00:00:00:06', ip='10.0.0.6/24' )
  h7 = net.addHost( 'h7', mac='00:00:00:00:00:07', ip='10.0.0.7/24' )
  h8 = net.addHost( 'h8', mac='00:00:00:00:00:08', ip='10.0.0.8/24' )

  s1 = net.addSwitch( 's1' )
  s2 = net.addSwitch( 's2' )
  s3 = net.addSwitch( 's3' )
  s4 = net.addSwitch( 's4' )
  s5 = net.addSwitch( 's5' )
  s6 = net.addSwitch( 's6' )

  c7 = net.addController( 'c7', controller=RemoteController, 
  ip='127.0.0.1', port=6633 )

  print("*** Creating links")
  net.addLink( h1, s1 )
  net.addLink( h2, s2 )
  net.addLink( h3, s3 )
  net.addLink( h4, s4 )
  net.addLink( h5, s4 )
  net.addLink( h6, s5 )
  net.addLink( h7, s5 )
  net.addLink( h8, s6 )

  net.addLink( s1, s2, cls=TCLink, bw=10               )
  net.addLink( s2, s3, cls=TCLink, bw=10               )
  net.addLink( s3, s4, cls=TCLink, bw=100, delay='5ms' )
  net.addLink( s4, s5, cls=TCLink, bw=100, delay='5ms' )
  net.addLink( s5, s6, cls=TCLink, bw=100              )
  net.addLink( s6, s1, cls=TCLink, bw=10               ) 

  print("*** Starting network")
  net.build()
  c7.start()
  s1.start( [c7] )
  s2.start( [c7] )
  s3.start( [c7] )
  s4.start( [c7] )
  s5.start( [c7] )
  s6.start( [c7] )

  # Configuring switches
  s1.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.1.0/24,actions=output:1")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.2.0/24,actions=output:2")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.3.0/24,actions=output:3")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.4.0/24,actions=output:3")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.5.0/24,actions=output:3")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.6.0/24,actions=output:2")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.7.0/24,actions=output:2")
  s1.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.8.0/24,actions=output:2")

  s2.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s2.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.1.0/24,actions=output:3")
  s2.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.2.0/24,actions=output:1")
  s2.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.3.0/24,actions=output:2")
  s2.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.4.0/24,actions=output:2")
  s2.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.5.0/24,actions=output:2")
  s2.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.6.0/24,actions=output:3")
  s2.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.7.0/24,actions=output:3")
  s2.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.8.0/24,actions=output:3")

  s3.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.1.0/24,actions=output:3")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.2.0/24,actions=output:3")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.3.0/24,actions=output:1")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.4.0/24,actions=output:2")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.5.0/24,actions=output:2")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.6.0/24,actions=output:2")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.7.0/24,actions=output:2")
  s3.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.8.0/24,actions=output:3")

  s4.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.1.0/24,actions=output:2")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.2.0/24,actions=output:2")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.3.0/24,actions=output:2")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.4.0/24,actions=output:1")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.5.0/24,actions=output:4")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.6.0/24,actions=output:3")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.7.0/24,actions=output:3")
  s4.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.8.0/24,actions=output:3")

  s5.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.1.0/24,actions=output:3")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.2.0/24,actions=output:3")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.3.0/24,actions=output:3")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.4.0/24,actions=output:2")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.5.0/24,actions=output:2")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.6.0/24,actions=output:1")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.7.0/24,actions=output:4")
  s5.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.8.0/24,actions=output:3")

  s6.cmd("sh ovs-ofctl add-flow s1 priority=1,arp,actions=flood")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.1.0/24,actions=output:3")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.2.0/24,actions=output:3")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.3.0/24,actions=output:3")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.4.0/24,actions=output:2")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.5.0/24,actions=output:2")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.6.0/24,actions=output:2")
  s6.cmd("ovs-ofctl add-flow s1 priority=10,ip,nw_dst=10.0.7.0/24,actions=output:2")
  s6.cmd("ovs-ofctl add-flow s1 
  priority=10,ip,nw_dst=10.0.8.0/24,actions=output:1")

  print("*** Running CLI")
  CLI( net )

  print("*** Stopping network")
  net.stop()


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

References

5. Dr. Chih-Heng Ke's Post #1 (Links don't work)
6. Dr. Chih-Heng Ke's Post #2 (Links don't work)