实验2：Open vSwitch虚拟交换机实践

实验2：Open vSwitch虚拟交换机实践
一、实验目的

能够对Open vSwitch进行基本操作；
能够通过命令行终端使用OVS命令操作Open vSwitch交换机，管理流表；
能够通过Mininet的Python代码运行OVS命令，控制网络拓扑中的Open vSwitch交换机

二、实验环境

Ubuntu 20.04 Desktop amd64
三、实验要求
（一）基本要求

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：

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

（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。

点击查看代码

#!/usr/bin/python

from mininet.net import Mininet
from mininet.node import Node
from mininet.link import Link
from mininet.log import  setLogLevel, info

def myNet():
    "Create network from scratch using Open vSwitch."

    info( "*** Creating nodes\n" )
    switch1 = Node( 's1', inNamespace=False )
    switch2 = Node( 's2', inNamespace=False )

    h1 = Node('h1')
    h2 = Node('h2')
    h3 = Node('h3')
    h4 = Node('h4')


    info( "*** Creating links\n" )
    Link(h1, switch1)
    Link(h2, switch1)
    Link(h3, switch2)
    Link(h4, switch2)
    Link(switch1, switch2)

    info( "*** Configuring hosts\n" )
    h1.setIP( '192.168.123.1/24' )
    h2.setIP( '192.168.124.1/24' )
    h3.setIP( '192.168.123.2/24' )
    h4.setIP( '192.168.124.2/24' )

    info( "*** Starting network using Open vSwitch\n" )
    switch1.cmd( 'ovs-vsctl del-br dp0' )
    switch1.cmd( 'ovs-vsctl add-br dp0' )
    switch2.cmd( 'ovs-vsctl del-br dp1' )
    switch2.cmd( 'ovs-vsctl add-br dp1' )


    for intf in switch1.intfs.values():
        print (intf)
        print (switch1.cmd( 'ovs-vsctl add-port dp0 %s' % intf ))


    for intf in switch2.intfs.values():
        print (intf)
        print (switch2.cmd( 'ovs-vsctl add-port dp1 %s' % intf ))

    print (switch1.cmd(r'ovs-vsctl show'))

    print (switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3'))
    print (switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3'))
    print (switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,dl_vlan=0,actions=pop_vlan,output:1'))
    print (switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,dl_vlan=1,actions=pop_vlan,output:2'))

    print (switch2.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3'))
    print (switch2.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3'))
    print (switch2.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,dl_vlan=0,actions=pop_vlan,output:1'))
    print (switch2.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,dl_vlan=1,actions=pop_vlan,output:2'))


    info( "*** Running test\n" )
    h1.cmdPrint( 'ping -c 3 ' + h3.IP() )
    h2.cmdPrint( 'ping -c 3 ' + h4.IP() )
    h1.cmdPrint( 'ping -c 3 ' + h4.IP() )
    h2.cmdPrint( 'ping -c 3 ' + h3.IP() )



    info( "*** Stopping network\n" )
    switch1.cmd( 'ovs-vsctl del-br dp0' )
    switch1.deleteIntfs()
    switch2.cmd( 'ovs-vsctl del-br dp1' )
    switch2.deleteIntfs()
    info( '\n' )

if __name__ == '__main__':
    setLogLevel( 'info' )
    info( '*** Scratch network demo (kernel datapath)\n' )
    Mininet.init()
    myNet()

四、个人总结
对于实验不是特别理解，在同学的帮助下才顺利的完成，需要理解的地方有很多，SDN并没有想象中的简单，要花费更多时间去把它消化。