实验2：Open vSwitch虚拟交换机实践

a) /home/用户名/学号/lab2/目录下执行ovs-vsctl show命令、以及p0和p1连通性测试的执行结果截图；

执行ovs-vsctl show命令

p0和p1连通性测试

b) /home/用户名/学号/lab2/目录下开启Mininet CLI并执行pingall命令的截图、上述目录下查看OVS流表的命令结果截图，wireshark抓包截图

pingall命令的截图

添加流表截图

OVS流表的命令结果截图

wireshark抓包截图

进阶要求

代码

点击查看代码

#!/usr/bin/env 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' )
    c0=net.addController(name='c0',
                      controller=Controller,
                      protocol='tcp',
                      port=6653)

    info( '*** Add switches\n')
    s2 = net.addSwitch('s2', cls=OVSKernelSwitch)
    s1 = net.addSwitch('s1', cls=OVSKernelSwitch)

    info( '*** Add hosts\n')
    h2 = net.addHost('h2', cls=Host, ip='10.0.0.2', defaultRoute=None)
    h4 = net.addHost('h4', cls=Host, ip='10.0.0.4', defaultRoute=None)
    h3 = net.addHost('h3', cls=Host, ip='10.0.0.3', defaultRoute=None)
    h1 = net.addHost('h1', cls=Host, ip='10.0.0.1', defaultRoute=None)

    info( '*** Add links\n')
    net.addLink(h2, s1,1,2)
    net.addLink(h1, s1,1,1)
    net.addLink(s1, s2,3,3)
    net.addLink(s2, h3,1,1)
    net.addLink(s2, h4,2,1)

    info( '*** Starting network\n')
    net.build()
    info( '*** Starting controllers\n')
    for controller in net.controllers:
        controller.start()

    info( '*** Starting switches\n')
    net.get('s2').start([c0])
    net.get('s1').start([c0])

    info( '*** Post configure switches and hosts\n')
    s1.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3')
    s1.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3')
    s1.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=0,actions=pop_vlan,output:1')
    s1.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=1,actions=pop_vlan,output:2')
    s2.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3')
    s2.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3')
    s2.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,dl_vlan=0,actions=pop_vlan,output:1')
    s2.cmd('sudo ovs-ofctl -O OpenFlow13 add-flow s2 priority=1,dl_vlan=1,actions=pop_vlan,output:2')



    CLI(net)
    net.stop()

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

进阶代码执行截图

个人总结

本次实验对我来说有一点麻烦，主要问题在于没有mininet的文档，对其相关命令不熟悉。
影响最大的问题是mininet生成的代码可以直接用 sudo python xxx.py来运行.--custom 参数要对应的函数名才行。可见平时动手需要自己主动思考。
然后是拓扑需要自己在代码上加上对应端口。需要另外开一个控制台窗口添加流表，保证网络拓扑的正常模拟工作。
这次实验让我对交换机有了更深的认识，对广播有了更直观认识。认识到了用于在二层交换机上分割广播域的技术称为VLAN。
再者对ovs-vsctl命令有了了解。第一次使用wireshark抓包，感觉很有意思。还学会了使用Python中的cmd来执行命令行。