I'm trying to create a topology in mininet, however if there are two paths from a hosts trough different switches, the hosts can't connect to each other.
Am I missing some sort of routing configuration? DO I have to manualy create paths and routing? I assumed the controllers did that on their own.
The code I'm using is re-purposed from the examples folder, the commented code is what prevents the hosts from reaching to each other:
#!/usr/bin/python
"""
This example creates a multi-controller network from semi-scratch by
using the net.add*() API and manually starting the switches and controllers.
This is the "mid-level" API, which is an alternative to the "high-level"
Topo() API which supports parametrized topology classes.
Note that one could also create a custom switch class and pass it into
the Mininet() constructor.
"""
from mininet.net import Mininet
from mininet.node import Controller, OVSSwitch
from mininet.cli import CLI
from mininet.log import setLogLevel, info
def multiControllerNet():
"Create a network from semi-scratch with multiple controllers."
net = Mininet( controller=Controller, switch=OVSSwitch )
info( "*** Creating (reference) controllers\n" )
c1 = net.addController( 'c1', port=6633 )
info( "*** Creating switches\n" )
sw1 = net.addSwitch('s1')
sw2 = net.addSwitch('s2')
sw3 = net.addSwitch('s3')
sw4 = net.addSwitch('s4')
sw5 = net.addSwitch('s5')
info( "*** Creating hosts\n" )
cl1 = net.addHost('c1')
cl2 = net.addHost('c2')
arca = net.addHost('arca')
ag1 = net.addHost('ag1')
ag2 = net.addHost('ag2')
ag3 = net.addHost('ag3')
tr1 = net.addHost('tr1')
tr2 = net.addHost('tr2')
info( "*** Creating links\n" )
net.addLink(cl1, sw1)
net.addLink(cl2, sw3)
net.addLink(arca, sw5)
# traffic generators
net.addLink(tr1, sw1)
net.addLink(tr2, sw5)
# aggregators
net.addLink(ag1, sw2)
net.addLink(ag2, sw2)
net.addLink(ag2, sw4)
net.addLink(ag3, sw4)
net.addLink(sw1, tr1)
net.addLink(sw5, tr2)
net.addLink(sw1, sw2)
#net.addLink(sw1, sw3)
net.addLink(sw2, sw3)
net.addLink(sw3, sw4)
#net.addLink(sw3, sw5)
net.addLink(sw4, sw5)
info( "*** Starting network\n" )
net.build()
c1.start()
sw1.start( [ c1 ] )
sw2.start( [ c1 ] )
sw3.start( [ c1 ] )
sw4.start( [ c1 ] )
sw5.start( [ c1 ] )
info( "*** Testing network\n" )
net.pingAll()
info( "*** Starting apps\n" )
info( "*** Running CLI\n" )
CLI( net )
info( "*** Stopping network\n" )
net.stop()
if __name__ == '__main__':
setLogLevel( 'info' ) # for CLI output
multiControllerNet()
What am I missing here?
This happens because Mininet does not ideally support loops in the network emulation. Read this link about Spanning Tree Algorithm in order to overcome this problem. Also see here.