I want create a net with two routers 4 switches and many host, but my router1 coudnt ping my router 2. It only work if i use IP-adress and pingall dont work for all hosts. Can anybody give my help?
I use a example of mininet example. ((h1-h3)-s1)-((h4-h7)-s2)-r1-r2-(s3-(h8-h10))-(s4-(h11-h14)).
I dont untwerstand what my problem is I have a Link of r0 to r1 and foward is = 1.

#!/usr/bin/env python


from mininet.topo import Topo
from mininet.net import Mininet
from mininet.node import Node
from mininet.log import setLogLevel, info
from mininet.cli import CLI

class LinuxRouter( Node ):
    "A Node with IP forwarding enabled."

    # pylint: disable=arguments-differ
    def config( self, **params ):
        super( LinuxRouter, self).config( **params )
        # Enable forwarding on the router
        self.cmd( 'sysctl net.ipv4.ip_forward=1' )

    def terminate( self ):
        self.cmd( 'sysctl net.ipv4.ip_forward=0' )
        super( LinuxRouter, self ).terminate()


class NetworkTopo( Topo ):
    "A LinuxRouter connecting three IP subnets"

    # pylint: disable=arguments-differ
    def build( self, **_opts ):

      
        router1 = self.addNode( 'r0', cls=LinuxRouter, ip=None )
        router2 = self.addNode( 'r1', cls=LinuxRouter, ip=None )
       
        s1, s2, s3, s4 = [ self.addSwitch( s ) for s in ( 's1', 's2', 's3', 's4' ) ]
        #add link switch to router and router to router 
        self.addLink( s1, router1, intfName2='r0-eth1',
                      params2={ 'ip' : '10.0.0.1/8' } )  # for clarity
        self.addLink( s2, router1, intfName2='r0-eth2',
                      params2={ 'ip' : '11.0.0.1/8' } )
        self.addLink( s3, router2, intfName2='r1-eth1',
                      params2={ 'ip' : '12.0.0.1/8' } )
        self.addLink( s4, router2, intfName2='r1-eth2',
                      params2={ 'ip' : '13.0.0.1/8' } )
        self.addLink( router1, router2,
                      intfName1='r0-eth3', params1={ 'ip' : '20.0.0.1/8' },
                      intfName2='r1-eth3', params2={ 'ip' : '20.0.0.2/8' } )
    

        #für N1 create host
        h1 = self.addHost( 'h1', ip='10.0.0.2/8',
                           defaultRoute='via 10.0.0.1' )
        h2 = self.addHost( 'h2', ip='10.0.0.3/8',
                           defaultRoute='via 10.0.0.1' )
        h3 = self.addHost( 'h3', ip='10.0.0.4/8',
                           defaultRoute='via 10.0.0.1' )
        #für N2
        h4 = self.addHost( 'h4', ip='11.0.0.2/8',
                           defaultRoute='via 11.0.0.1' )
        h5 = self.addHost( 'h5', ip='11.0.0.3/8',
                           defaultRoute='via 11.0.0.1' )
        h6 = self.addHost( 'h6', ip='11.0.0.4/8',
                           defaultRoute='via 11.0.0.1' )
        h7 = self.addHost( 'h7', ip='11.0.0.5/8',
                           defaultRoute='via 11.0.0.1' )
        #für N3
        h8 = self.addHost( 'h8', ip='12.0.0.2/8',
                           defaultRoute='via 12.0.0.1' )
        h9 = self.addHost( 'h9', ip='12.0.0.3/8',
                           defaultRoute='via 12.0.0.1' )
        h10 = self.addHost( 'h10', ip='12.0.0.4/24',
                           defaultRoute='via 12.0.0.1' )
         #Für N4
        h11 = self.addHost( 'h11', ip='13.0.0.2/8',
                           defaultRoute='via 13.0.0.1' )
        h12 = self.addHost( 'h12', ip='13.0.0.3/8',
                           defaultRoute='via 13.0.0.1' )
        h13 = self.addHost( 'h13', ip='13.0.0.4/8',
                           defaultRoute='via 13.0.0.1' )
        h14 = self.addHost( 'h14', ip='13.0.0.5/8',
                           defaultRoute='via 13.0.0.1' )
      

        #add link switch to host
        for h, s in [ (h1, s1), (h2, s1), (h3, s1),
                  (h4, s2), (h5, s2), (h6, s2), (h7, s2),
                  (h8, s3), (h9, s3), (h10, s3),
                  (h11, s4), (h12, s4), (h13, s4), (h14, s4)]:
            self.addLink( h, s )

def run():
    "Test linux router"
    topo = NetworkTopo()
    net = Mininet( topo=topo,
                   waitConnected=True )  # controller is used by s1-s3
    net.start()
    info( '*** Routing Table on Router:n' )
    info( net[ 'r0' ].cmdPrint( 'route' ) )
    info( net[ 'r1' ].cmdPrint( 'route' ) )

    CLI( net )
    net.stop()

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