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networkingtcproutesmininet

linux shell cmd is not working for mininet host


I am trying to setup a mininet topology consisting one switch connected to three host. The below code does exactly the same thing and bring up the topology fine. But i see, none of the host.cmd is taking effect. If i copy paste the commands on the device console, then they work fine.

The below command just dont work :

h1.cmd('ifconfig lo 122.1.1.1 netmask 255.255.255.255')

similarly, the below command configures the mac but not the IP on the interface.

link_h1s1.intf1.config(ip='100.168.0.1/24', mac = '00:00:00:00:00:01')

Looks like the problem if specific to hosts. At the end of the program i paste the output topology.

somebody expert with working with mininet pls help

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

#reference : http://intronetworks.cs.luc.edu/current/html/mininet.html

def topology():

    net = Mininet()

    #Add Controller to the Topology
    c0 = net.addController( 'c0',
         controller=DefaultController)

    # Add hosts and switches
    h1 = net.addHost( 'h1')
    h2 = net.addHost( 'h2')
    h3 = net.addHost( 'h3')

    #Add L2 Switch
    s1 = net.addSwitch( 's1')

    #Add links
    link_h1s1 = net.addLink( h1, s1 , intfName1 = 'h1-s1', intfName2 = 's1-h1')
    link_h2s1 = net.addLink( h2, s1 , intfName1 = 'h2-s1', intfName2 = 's1-h2')
    link_h3s1 = net.addLink( h3, s1 , intfName1 = 'h3-s1', intfName2 = 's1-h3')

    link_h1s1.intf1.config(ip='100.168.0.1/24', mac = '00:00:00:00:00:01')
    link_h2s1.intf1.config(ip='100.168.0.2/24', mac = '00:00:00:00:00:02')
    link_h3s1.intf1.config(ip='100.168.0.3/24', mac = '00:00:00:00:00:03')

    link_h1s1.intf2.config(ip=None, mac = '00:00:00:00:00:04')
    link_h2s1.intf2.config(ip=None, mac = '00:00:00:00:00:05')
    link_h3s1.intf2.config(ip=None, mac = '00:00:00:00:00:06')


    #h1.setIP('122.1.1.1/32')
    h1.cmd('ifconfig h1-s1 100.168.0.1 netmask 255.255.255.0')
    h2.cmd('ifconfig h2-s1 100.168.0.2 netmask 255.255.255.0')
    h3.cmd('ifconfig h3-s1 100.168.0.3 netmask 255.255.255.0')

    #Setting lo IP addresses
    h1.cmd('ifconfig lo 122.1.1.1 netmask 255.255.255.255')
    h2.cmd('ifconfig lo 122.1.1.2 netmask 255.255.255.255')
    h3.cmd('ifconfig lo 122.1.1.3 netmask 255.255.255.255')

    #finished building the Topology
    net.build()

    #Star the Controller
    #c0.start()

    #start the Switches
    #s1.start( [c0] )

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

    CLI( net )

    print "*** Stopping network"

    net.stop()

if __name__ == '__main__':

    setLogLevel( 'info' )

    topology()

output of host h1

mininet> h1 ifconfig
h1-s1     Link encap:Ethernet  HWaddr 00:00:00:00:00:01
          inet addr:10.0.0.1  Bcast:10.255.255.255  Mask:255.0.0.0   << default IP 10.1.1.1/8 is taken
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.255.255.255                 << Default loopback addr is taken
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Solution

  • you should build the network before running the commands

    from mininet.net import Mininet
    from mininet.node import Controller, OVSKernelSwitch, UserSwitch, DefaultController
    from mininet.cli import CLI
    from mininet.log import setLogLevel, info
    from mininet.link import Link, TCLink
    
    #reference : http://intronetworks.cs.luc.edu/current/html/mininet.html
    
    def topology():
    
        net = Mininet()
    
        #Add Controller to the Topology
        c0 = net.addController( 'c0',
             controller=DefaultController)
    
        # Add hosts and switches
        h1 = net.addHost( 'h1')
        h2 = net.addHost( 'h2')
        h3 = net.addHost( 'h3')
    
        #Add L2 Switch
        s1 = net.addSwitch( 's1')
    
        #Add links
        link_h1s1 = net.addLink( h1, s1 , intfName1 = 'h1-s1', intfName2 = 's1-h1')
        link_h2s1 = net.addLink( h2, s1 , intfName1 = 'h2-s1', intfName2 = 's1-h2')
        link_h3s1 = net.addLink( h3, s1 , intfName1 = 'h3-s1', intfName2 = 's1-h3')
    
        link_h1s1.intf1.config(ip='100.168.0.1/24', mac = '00:00:00:00:00:01')
        link_h2s1.intf1.config(ip='100.168.0.2/24', mac = '00:00:00:00:00:02')
        link_h3s1.intf1.config(ip='100.168.0.3/24', mac = '00:00:00:00:00:03')
    
        link_h1s1.intf2.config(ip=None, mac = '00:00:00:00:00:04')
        link_h2s1.intf2.config(ip=None, mac = '00:00:00:00:00:05')
        link_h3s1.intf2.config(ip=None, mac = '00:00:00:00:00:06')
        net.build()
        net.start()
    
        #h1.setIP('122.1.1.1/32')
        h1.cmd('ifconfig h1-s1 100.168.0.1 netmask 255.255.255.0')
        h2.cmd('ifconfig h2-s1 100.168.0.2 netmask 255.255.255.0')
        h3.cmd('ifconfig h3-s1 100.168.0.3 netmask 255.255.255.0')
    
        #Setting lo IP addresses
        h1.cmd('ifconfig lo 122.1.1.1 netmask 255.255.255.255')
        h2.cmd('ifconfig lo 122.1.1.2 netmask 255.255.255.255')
        h3.cmd('ifconfig lo 122.1.1.3 netmask 255.255.255.255')
    
    
        #Star the Controller
        #c0.start()
    
        #start the Switches
        #s1.start( [c0] )
    
        print "*** Running CLI"
    
        CLI( net )
    
        print "*** Stopping network"
    
        net.stop()
    
    if __name__ == '__main__':
    
        setLogLevel( 'info' )
    
        topology()
    

    Output:

    root@grisou-50:~/mininet# python test.py
    *** Configuring hosts
    h1 h2 h3
    *** Starting controller
    c0
    *** Starting 1 switches
    s1 ...
    *** Running CLI
    *** Starting CLI:
    mininet> ifconfig
    *** Unknown command: ifconfig
    mininet> h1 ifconfig
    h1-s1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 100.168.0.1  netmask 255.255.255.0  broadcast 100.168.0.255
            inet6 fe80::200:ff:fe00:1  prefixlen 64  scopeid 0x20<link>
            ether 00:00:00:00:00:01  txqueuelen 1000  (Ethernet)
            RX packets 19  bytes 1626 (1.6 KB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 9  bytes 806 (806.0 B)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
            inet 122.1.1.1  netmask 255.255.255.255
            inet6 ::1  prefixlen 128  scopeid 0x10<host>
            loop  txqueuelen 1000  (Local Loopback)
            RX packets 0  bytes 0 (0.0 B)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 0  bytes 0 (0.0 B)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    mininet>
    

    A cleanest solution can be to directly set the Ip of the hosts in the addHost function. In this case if you call dump from the CLI you should see the Ips correctly set.

    from mininet.net import Mininet
    from mininet.node import Controller, OVSKernelSwitch, UserSwitch, DefaultController
    from mininet.cli import CLI
    from mininet.log import setLogLevel, info
    from mininet.link import Link, TCLink
    
    #reference : http://intronetworks.cs.luc.edu/current/html/mininet.html
    
    def topology():
    
        net = Mininet()
    
        #Add Controller to the Topology
        c0 = net.addController( 'c0',
             controller=DefaultController)
    
        # Add hosts and switches
        h1 = net.addHost( 'h1', ip='100.168.0.1/24', mac = '00:00:00:00:00:01')
        h2 = net.addHost( 'h2', ip='100.168.0.2/24', mac = '00:00:00:00:00:02')
        h3 = net.addHost( 'h3', ip='100.168.0.3/24', mac = '00:00:00:00:00:03')
    
        #Add L2 Switch
        s1 = net.addSwitch( 's1')
    
        #Add links
        link_h1s1 = net.addLink( h1, s1 , intfName1 = 'h1-s1', intfName2 = 's1-h1')
        link_h2s1 = net.addLink( h2, s1 , intfName1 = 'h2-s1', intfName2 = 's1-h2')
        link_h3s1 = net.addLink( h3, s1 , intfName1 = 'h3-s1', intfName2 = 's1-h3')
    
        link_h1s1.intf2.config(ip=None, mac = '00:00:00:00:00:04')
        link_h2s1.intf2.config(ip=None, mac = '00:00:00:00:00:05')
        link_h3s1.intf2.config(ip=None, mac = '00:00:00:00:00:06')
        net.build()
        net.start()
    
    
        #Setting lo IP addresses
        h1.cmd('ifconfig lo 122.1.1.1 netmask 255.255.255.255')
        h2.cmd('ifconfig lo 122.1.1.2 netmask 255.255.255.255')
        h3.cmd('ifconfig lo 122.1.1.3 netmask 255.255.255.255')
    
    
        #Star the Controller
        #c0.start()
    
        #start the Switches
        #s1.start( [c0] )
    
        print "*** Running CLI"
    
        CLI( net )
    
        print "*** Stopping network"
    
        net.stop()
    
    if __name__ == '__main__':
    
        setLogLevel( 'info' )
    
        topology()