实验2：Open vSwitch虚拟交换机实践

目录

• 一、基础要求
  • a)1 /home/用户名/学号/lab2/目录下执行ovs-vsctl show命令
  • a)2 p0和p1连通性测试的执行结果
  • b)1 /home/用户名/学号/lab2/目录下开启Mininet CLI并执行pingall命令
  • b)2 上述目录下查看OVS流表的命令结果
  • b)3 wireshark抓包
• 二、进阶要求
  • 1. 代码
  • 2. 执行结果
• 四、个人感想

一、基础要求

a)1 /home/用户名/学号/lab2/目录下执行ovs-vsctl show命令

a)2 p0和p1连通性测试的执行结果

b)1 /home/用户名/学号/lab2/目录下开启Mininet CLI并执行pingall命令

b)2 上述目录下查看OVS流表的命令结果

b)3 wireshark抓包

二、进阶要求

阅读SDNLAB实验使用Mininet，编写Python代码，生成（一）中的SDN拓扑，并在代码中直接使用OVS命令，做到可以直接运行Python程序完成和（一）相同的VLAN划分。

1. 代码

    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='10.0.0.1/24')

        info( '*** Adding controller\n' )
        c0=net.addController(name='c0',
                          controller=Controller,
                          protocol='tcp',
                          port=6633)

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

        info( '*** Add hosts\n')
        h1 = net.addHost('h1', cls=Host, ip='10.0.0.1/24', defaultRoute=None)
        h2 = net.addHost('h2', cls=Host, ip='10.0.0.2/24', defaultRoute=None)
        h3 = net.addHost('h3', cls=Host, ip='10.0.0.3/24', defaultRoute=None)
        h4 = net.addHost('h4', cls=Host, ip='10.0.0.4/24', defaultRoute=None)

        info( '*** Add links\n')
        net.addLink(h1, s1, 1, 1)
        net.addLink(s1, h2, 2, 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('s1').start([c0])
        net.get('s2').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()

2. 执行结果

四、个人感想

通过这次实验，我复习了mininet可视化工具生成拓扑、命令行生成特定拓扑、mininet交互界面管理SDN拓扑和使用python脚本构建SDN拓扑。在实验过程中进阶遇到过执行不了情况，经过查找和舍友的帮助，发现需要用mn -c释放之前创建拓扑时占用的未释放的资源,解决了问题