这次的拓扑是一个主机拥有两个接口，两个接口分别有不同的网关，拓扑图如下，拓扑可以通过前两篇中提到的miniedit.py去生成：

主要配置指令如下：

截得不全直接看代码吧

#!/usr/bin/python

from mininet.net import Mininet
from mininet.node import Controller, RemoteController, OVSController
from mininet.node import CPULimitedHost, Host, Node
from mininet.node import OVSKernelSwitch, UserSwitch
from mininet.node import IVSSwitch
from mininet.cli import CLI
from mininet.log import setLogLevel, info
from mininet.link import TCLink, Intf
from subprocess import call

def myNetwork():

    net = Mininet( topo=None,
                   build=False,
                   ipBase='10.0.0.0/8')

    info( '*** Adding controller\n' )
    info( '*** Add switches\n')
    r1 = net.addHost('r1', cls=Node, ip='0.0.0.0')
    r2 = net.addHost('r2', cls=Node, ip='0.0.0.0')
    r3 = net.addHost('r3', cls=Node, ip='0.0.0.0')
    info( '*** Add hosts\n')
    h1 = net.addHost('h1', cls=Host, ip='10.0.0.2/24', defaultRoute=None)
    h2 = net.addHost('h2', cls=Host, ip='10.0.1.2/24', defaultRoute=None)
    
    info( '*** Add links\n')
    net.addLink(h1, r1)
    net.addLink(h1, r3)
    net.addLink(r1, r2)
    net.addLink(r2, h2)
    net.addLink(r3, r2)
    
    info( '*** Starting network\n')
    net.build()
    info( '*** Starting controllers\n')
    for controller in net.controllers:
        controller.start()

    info( '*** Starting switches\n')
    h1.cmd('ifconfig h1-eth0 0')
    h1.cmd('ifconfig h1-eth1 0')
    h2.cmd('ifconfig h2-eth0 0')
    r1.cmd('ifconfig r1-eth0 0')
    r1.cmd('ifconfig r1-eth1 0')
    r2.cmd('ifconfig r2-eth0 0')
    r2.cmd('ifconfig r2-eth1 0')
    r2.cmd('ifconfig r2-eth2 0')
    r3.cmd('ifconfig r3-eth0 0')
    r3.cmd('ifconfig r3-eth1 0')
    r1.cmd('sysctl -w net.ipv4.ip_forward=1')
    r2.cmd('sysctl -w net.ipv4.ip_forward=1')
    r3.cmd('sysctl -w net.ipv4.ip_forward=1')
    info( '*** Post configure switches and hosts\n')
    h1.cmd('ifconfig h1-eth0 10.0.0.2/24')
    h1.cmd('ifconfig h1-eth1 10.0.2.2/24')
    h2.cmd('ifconfig h2-eth0 10.0.1.2/24')
    r1.cmd('ifconfig r1-eth0 10.0.0.1/24')
    r1.cmd('ifconfig r1-eth1 172.16.2.1/24')
    r2.cmd('ifconfig r2-eth0 172.16.2.2/24')
    r2.cmd('ifconfig r2-eth1 10.0.1.1/24')
    r2.cmd('ifconfig r2-eth2 192.168.2.2/24')
    r3.cmd('ifconfig r3-eth0 10.0.2.1/24')
    r3.cmd('ifconfig r3-eth1 192.168.2.1/24')

    r1.cmd('route add -net 10.0.1.0/24 gw 172.16.2.2')
    r2.cmd('route add -net 10.0.0.0/24 gw 172.16.2.1')
    r2.cmd('route add -net 10.0.2.0/24 gw 192.168.2.1') 
    r3.cmd('route add -net 10.0.1.0/24 gw 192.168.2.2')
    h1.cmd("ip rule add from 10.0.0.2 table 1")
    h1.cmd("ip rule add from 10.0.2.2 table 2")
    h1.cmd("ip route add 10.0.0.0/24 dev h1-eth0 scope link table 1")
    h1.cmd("ip route add default via 10.0.0.1 dev h1-eth0 table 1")
    h1.cmd("ip route add 10.0.2.0/24 dev h1-eth1 scope link table 2")
    h1.cmd("ip route add default via 10.0.2.1 dev h1-eth1 table 2")
    h1.cmd("ip route add default scope global nexthop via 10.0.0.1 dev h1-eth0") 
    h2.cmd("ip rule add from 10.0.1.2 table 1")
    h2.cmd("ip route add 10.0.1.0/24 dev h2-eth0 scope link table 1")
    h2.cmd("ip route add default via 10.0.1.1 dev h2-eth0 table 1")
    h2.cmd("ip route add default scope global nexthop via 10.0.1.1 dev h2-eth0")

    CLI(net)
    net.stop()

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