一、实验目的

  • Mininet 安装之后，会连带安装 Open vSwitch，可以直接通过 Python 脚本调用Open vSwitch 命令，从而直接控制 Open vSwitch，通过实验了解调用控制的方法。

    二、实验任务

  • 在本实验中，使用 Mininet 基于 Python 的脚本，调用“ovs-vsctl”命令直接控制Open vSwitch。使用默认的交换机泛洪规则，设置更高的优先级规则进行预先定义 IP 报文的转发。在多个交换机中通过设置不同 TOS 值的数据包将通过不同的方式到达目的地址，验证主机间的连通性及到达目的地址的时间。

    三、实验步骤

    1. 实验环境

  • Ryu虚拟机

    2. 实验步骤

    （1）创建 ovsSingleBr.py 脚本并运行

  • 实验内容
    执行 ovsSingleBr.py，在没有控制器的情况下，在Mininet 脚本中通过调用 ovs 命令直接向 switch0 交换机下发流表，将入端口号为1/2/3 的数据包泛洪广播，并对目的地址为 192.168.123.1/2/3 的数据包分别从1/2/3 端口转发出去。之后测试 h0 ping h1，h0 ping h2，网络连通。

  • ovsSingleBr.py 对应拓扑

Open vSwitch 实验——Mininet 中使用 OVS 命令 - 图1

  • ovsSingleBr.py 对应代码

image.png

  1. #!/usr/bin/python
  3. from mininet.net import Mininet
  4. from mininet.node import Node
  5. from mininet.link import Link
  6. from mininet.log import  setLogLevel, info
  8. def myNet():
  9.     "Create network from scratch using Open vSwitch."
  11.     info( "*** Creating nodes\n" )
  12.     switch0 = Node( 's0', inNamespace=False )
  14.     h0 = Node( 'h0' )
  15.     h1 = Node( 'h1' )
  16.     h2 = Node( 'h2' )
  18.     info( "*** Creating links\n" )
  19.     Link( h0, switch0)
  20.     Link( h1, switch0)
  21.     Link( h2, switch0)
  23.     info( "*** Configuring hosts\n" )
  24.     h0.setIP( '192.168.123.1/24' )
  25.     h1.setIP( '192.168.123.2/24' )
  26.     h2.setIP( '192.168.123.3/24' )
  28.     info( "*** Starting network using Open vSwitch\n" )
  29.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  30.     switch0.cmd( 'ovs-vsctl add-br dp0' )
  32.     for intf in switch0.intfs.values():
  33.         print intf
  34.         print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )
  36.     # Note: controller and switch are in root namespace, and we
  37.     # can connect via loopback interface
  38.     #switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:127.0.0.1:6633' )
  40.     print switch0.cmd(r'ovs-vsctl show')
  42.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=1,actions=flood' ) 
  43.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=2,actions=flood' )
  44.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=3,actions=flood' )
  46.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.1,actions=output:1' ) 
  47.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,actions=output:2' ) 
  48.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.3,actions=output:3')
  50.     #switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &')
  51.     #h0.cmd('tcpdump -i h0-eth0 -U -w aaa &')
  52.     info( "*** Running test\n" )
  53.     h0.cmdPrint( 'ping -c 3 ' + h1.IP() )
  54.     h0.cmdPrint( 'ping -c 3 ' + h2.IP() )
  56.     #print switch0.cmd( 'ovs-ofctl show dp0' )    
  57.     #print switch0.cmd( 'ovs-ofctl dump-tables  dp0' )
  58.     #print switch0.cmd( 'ovs-ofctl dump-ports   dp0' )
  59.     #print switch0.cmd( 'ovs-ofctl dump-flows  dp0' )
  60.     #print switch0.cmd( 'ovs-ofctl dump-aggregate  dp0' )
  61.     #print switch0.cmd( 'ovs-ofctl queue-stats dp0' )
  63.     info( "*** Stopping network\n" )
  64.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  65.     switch0.deleteIntfs()
  66.     info( '\n' )
  68. if __name__ == '__main__':
  69.     setLogLevel( 'info' )
  70.     info( '*** Scratch network demo (kernel datapath)\n' )
  71.     Mininet.init()
  72.     myNet()
  • 运行结果

image.png
image.png
image.png
image.png

（2）创建 ovsMultiBr.py 脚本并运行

  • 实验内容

在没有控制器的情况下，在Mininet 脚本中通过调用 ovs 命令给多个交换机下发流表，通过 h0 ping h1 操作测试验证主机间的连通性，并通过-Q 参数设置不通的 tos 值查看主机间的连通性。通过验证发现，tos 值设置越大，时间使用越少。

  • ovsMultiBr.py 对应拓扑

Open vSwitch 实验——Mininet 中使用 OVS 命令 - 图7

  • ovsMultiBr.py 对应代码

image.png

  1. #!/usr/bin/python
  3. from mininet.net import Mininet
  4. from mininet.node import Node
  5. from mininet.link import TCLink
  6. from mininet.log import  setLogLevel, info
  8. def myNet():
  9.     "Create network from scratch using Open vSwitch."
  11.     info( "*** Creating nodes\n" )
  12.     switch0 = Node( 's0', inNamespace=False )
  13.     switch1 = Node( 's1', inNamespace=False )
  14.     switch2 = Node( 's2', inNamespace=False )
  15.     switch3 = Node( 's3', inNamespace=False )
  16.     switch4 = Node( 's4', inNamespace=False )
  17.     h0 = Node( 'h0' )
  18.     h1 = Node( 'h1' )
  20.     info( "*** Creating links\n" )
  21.     linkopts0=dict(bw=100, delay='1ms', loss=0)
  22.     linkopts1=dict(bw=1, delay='100ms', loss=0)
  23.     linkopts2=dict(bw=10, delay='50ms', loss=0)
  24.     linkopts3=dict(bw=100, delay='1ms', loss=0)
  25.     TCLink( h0, switch0, **linkopts0)
  26.     TCLink( switch0, switch1, **linkopts0)
  27.     TCLink( switch0, switch2, **linkopts0)
  28.     TCLink( switch0, switch3, **linkopts0)
  29.     TCLink( switch1, switch4, **linkopts1)
  30.     TCLink( switch2, switch4, **linkopts2)
  31.     TCLink( switch3, switch4, **linkopts3)
  32.     TCLink( h1, switch4, **linkopts0)
  34.     info( "*** Configuring hosts\n" )
  35.     h0.setIP( '192.168.123.1/24' )
  36.     h1.setIP( '192.168.123.2/24' )
  37.     info( str( h0 ) + '\n' )
  38.     info( str( h1 ) + '\n' )
  40.     info( "*** Starting network using Open vSwitch\n" )
  41.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  42.     switch0.cmd( 'ovs-vsctl add-br dp0' )
  43.     switch1.cmd( 'ovs-vsctl del-br dp1' )
  44.     switch1.cmd( 'ovs-vsctl add-br dp1' )
  45.     switch2.cmd( 'ovs-vsctl del-br dp2' )
  46.     switch2.cmd( 'ovs-vsctl add-br dp2' )
  47.     switch3.cmd( 'ovs-vsctl del-br dp3' )
  48.     switch3.cmd( 'ovs-vsctl add-br dp3' )
  49.     switch4.cmd( 'ovs-vsctl del-br dp4' )
  50.     switch4.cmd( 'ovs-vsctl add-br dp4' )
  52.     for intf in switch0.intfs.values():
  53.         print intf
  54.         print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )
  56.     for intf in switch1.intfs.values():
  57.         print intf
  58.         print switch1.cmd( 'ovs-vsctl add-port dp1 %s' % intf )
  60.     for intf in switch2.intfs.values():
  61.         print intf
  62.         print switch2.cmd( 'ovs-vsctl add-port dp2 %s' % intf )
  64.     for intf in switch3.intfs.values():
  65.         print intf
  66.         print switch3.cmd( 'ovs-vsctl add-port dp3 %s' % intf )
  68.     for intf in switch4.intfs.values():
  69.         print intf
  70.         print switch4.cmd( 'ovs-vsctl add-port dp4 %s' % intf )
  72.     print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=1,actions=flood' )
  73.     print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=1,actions=output:2' ) 
  74.     print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=2,actions=output:1' )
  75.     print switch2.cmd(r'ovs-ofctl add-flow dp2 idle_timeout=0,priority=1,in_port=1,actions=output:2' )
  76.     print switch2.cmd(r'ovs-ofctl add-flow dp2 idle_timeout=0,priority=1,in_port=2,actions=output:1' )
  77.     print switch3.cmd(r'ovs-ofctl add-flow dp3 idle_timeout=0,priority=1,in_port=1,actions=output:2' )    
  78.     print switch3.cmd(r'ovs-ofctl add-flow dp3 idle_timeout=0,priority=1,in_port=2,actions=output:1' )
  79.     print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=1,actions=output:4' )
  80.     print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=2,actions=output:4' )
  81.     print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=3,actions=output:4' )
  82.     print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=4,actions=output:3' )
  84.     #print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,actions=output:4')
  85.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x10,actions=output:2') 
  86.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x20,actions=output:3')
  87.     print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x30,actions=output:4') 
  88.     #print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.1,actions=output:1')
  90.     #switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &')
  91.     #h0.cmd('tcpdump -i h0-eth0 -U -w aaa &')
  92.     info( "*** Running test\n" )
  93.     h0.cmdPrint( 'ping -Q 0x10 -c 3 ' + h1.IP() )
  94.     h0.cmdPrint( 'ping -Q 0x20 -c 3 ' + h1.IP() )
  95.     h0.cmdPrint( 'ping -Q 0x30 -c 3 ' + h1.IP() )
  96.     #h1.cmdPrint('iperf -s -p 12345 -u &')
  97.     #h0.cmdPrint('iperf -c ' + h1.IP() +' -u -b 10m -p 12345 -t 10 -i 1')
  99.     #print switch0.cmd( 'ovs-ofctl show dp0' )    
  100.     #print switch1.cmd( 'ovs-ofctl show dp1' )
  101.     #print switch2.cmd( 'ovs-ofctl show dp2' )
  102.     #print switch3.cmd( 'ovs-ofctl show dp3' )
  103.     #print switch4.cmd( 'ovs-ofctl show dp4' )  
  104.     #print switch0.cmd( 'ovs-ofctl dump-tables  dp0' )
  105.     #print switch0.cmd( 'ovs-ofctl dump-ports   dp0' )
  106.     #print switch0.cmd( 'ovs-ofctl dump-flows  dp0' )
  107.     #print switch0.cmd( 'ovs-ofctl dump-aggregate  dp0' )
  108.     #print switch0.cmd( 'ovs-ofctl queue-stats dp0' )
  110.     #print "Testing video transmission between h1 and h2"
  111.     #h1.cmd('./myrtg_svc -u > myrd &')
  112.     #h0.cmd('./mystg_svc -trace st 192.168.123.2')
  114.     info( "*** Stopping network\n" )
  115.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  116.     switch0.deleteIntfs()
  117.     switch1.cmd( 'ovs-vsctl del-br dp1' )
  118.     switch1.deleteIntfs()
  119.     switch2.cmd( 'ovs-vsctl del-br dp2' )
  120.     switch2.deleteIntfs()
  121.     switch3.cmd( 'ovs-vsctl del-br dp3' )
  122.     switch3.deleteIntfs()
  123.     switch4.cmd( 'ovs-vsctl del-br dp4' )
  124.     switch4.deleteIntfs()
  125.     info( '\n' )
  127. if __name__ == '__main__':
  128.     setLogLevel( 'info' )
  129.     info( '*** Scratch network demo (kernel datapath)\n' )
  130.     Mininet.init()
  131.     myNet()
  • 运行结果

image.png
image.png
image.png

（3） 创建 vlanBr.py 脚本并运行

  • 实验内容

尝试修改代码，利用 ovs 命令直接下发 VLAN 设置的流表项，最终测试 h0 和 h2 互通，h1 和 h3 互通，其余主机均不通

  • vlanBr.py对应拓扑

Open vSwitch 实验——Mininet 中使用 OVS 命令 - 图12

  • vlanBr.py对应代码

image.png

  1. #!/usr/bin/python
  3. from mininet.net import Mininet
  4. from mininet.node import Node
  5. from mininet.link import TCLink
  6. from mininet.log import  setLogLevel, info
  8. def myNet():
  9.     "Create network from scratch using Open vSwitch."
  11.     info( "*** Creating nodes\n" )
  12.     switch0 = Node( 's0', inNamespace=False )
  13.     switch1 = Node( 's1', inNamespace=False )
  14.     h0 = Node( 'h0' )
  15.     h1 = Node( 'h1' )
  16.     h2 = Node( 'h2' )
  17.     h3 = Node( 'h3' )
  19.     info( "*** Creating links\n" )
  20.     linkopts0=dict(bw=100, delay='1ms', loss=0)
  21.     linkopts1=dict(bw=1, delay='100ms', loss=0)
  22.     linkopts2=dict(bw=10, delay='50ms', loss=0)
  23.     TCLink( switch0, switch1, **linkopts0)
  24.     TCLink( h0, switch0, **linkopts1)
  25.     TCLink( h2, switch1, **linkopts1)
  26.     TCLink( h1, switch0, **linkopts2)
  27.     TCLink( h3, switch1, **linkopts2)    
  29.     info( "*** Configuring hosts\n" )
  30.     h0.setIP( '192.168.123.1/24' )
  31.     h1.setIP( '192.168.123.2/24' )
  32.     h2.setIP( '192.168.123.3/24' )
  33.     h3.setIP( '192.168.123.4/24' )
  34.     info( str( h0 ) + '\n' )
  35.     info( str( h1 ) + '\n' )
  36.     info( str( h2 ) + '\n' )
  37.     info( str( h3 ) + '\n' )
  39.     info( "*** Starting network using Open vSwitch\n" )
  40.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  41.     switch0.cmd( 'ovs-vsctl add-br dp0' )
  42.     switch1.cmd( 'ovs-vsctl del-br dp1' )
  43.     switch1.cmd( 'ovs-vsctl add-br dp1' )
  44.     for intf in switch0.intfs.values():
  45.         print intf
  46.         print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )
  47.     for intf in switch1.intfs.values():
  48.         print intf
  49.         print switch1.cmd( 'ovs-vsctl add-port dp1 %s' % intf )
  50.     print switch0.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' )
  51.     print switch0.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' )
  52.     print switch0.cmd(r'sudo ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,dl_vlan=0,actions=pop_vlan,output:1' )
  53.     print switch0.cmd(r'sudo ovs-ofctl -O OpenFlow13 add-flow dp0 priority=1,dl_vlan=1,actions=pop_vlan,output:2' )
  54.     print switch1.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' )
  55.     print switch1.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' )
  56.     print switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,dl_vlan=0,actions=pop_vlan,output:1' )
  57.     print switch1.cmd(r'ovs-ofctl -O OpenFlow13 add-flow dp1 priority=1,dl_vlan=1,actions=pop_vlan,output:2' )
  58.     #switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &')
  59.     #h0.cmd('tcpdump -i h0-eth0 -U -w aaa &')
  60.     info( "*** Running test\n" )
  61.     h0.cmdPrint( 'ping -Q 0x10 -c 3 ' + h1.IP() )
  62.     h0.cmdPrint( 'ping -Q 0x20 -c 3 ' + h2.IP() )
  63.     h0.cmdPrint( 'ping -Q 0x30 -c 3 ' + h3.IP() )
  64.     h1.cmdPrint( 'ping -Q 0x40 -c 3 ' + h2.IP() )
  65.     h1.cmdPrint( 'ping -Q 0x50 -c 3 ' + h3.IP() )
  66.     h2.cmdPrint( 'ping -Q 0x60 -c 3 ' + h3.IP() )
  67.     #h1.cmdPrint('iperf -s -p 12345 -u &')
  68.     #h0.cmdPrint('iperf -c ' + h1.IP() +' -u -b 10m -p 12345 -t 10 -i 1')
  69.     info( "*** Stopping network\n" )
  70.     switch0.cmd( 'ovs-vsctl del-br dp0' )
  71.     switch0.deleteIntfs()
  72.     switch1.cmd( 'ovs-vsctl del-br dp1' )
  73.     switch1.deleteIntfs()
  74.     info( '\n' )
  75. if __name__ == '__main__':
  76.     setLogLevel( 'info' )
  77.     info( '*** Scratch network demo (kernel datapath)\n' )
  78.     Mininet.init()
  79.     myNet()
  • 运行结果

image.png
image.png
image.png