基础要求
a)
创建OVS交换机，以ovs-032002441命名。在创建的交换机上增加端口p0和p1，设置p0的端口号为100，p1的端口号为101，类型均为internal；创建虚拟网络空间ns0和ns1，分别将p0和p1移入，并分别配置p0和p1端口的ip地址为190.168.0.100、192.168.0.101，子网掩码为255.255.255.0；最后测试p0和p1的连通性
Mininet下发流表
进阶要求
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 ))
# Note: controller and switch are in root namespace, and we
# can connect via loopback interface
#switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:127.0.0.1:6633' )
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'))
#switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &')
#h0.cmd('tcpdump -i h0-eth0 -U -w aaa &')
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() )
#print switch0.cmd( 'ovs-ofctl show dp0' )
#print switch0.cmd( 'ovs-ofctl dump-tables dp0' )
#print switch0.cmd( 'ovs-ofctl dump-ports dp0' )
#print switch0.cmd( 'ovs-ofctl dump-flows dp0' )
#print switch0.cmd( 'ovs-ofctl dump-aggregate dp0' )
#print switch0.cmd( 'ovs-ofctl queue-stats dp0' )
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()
`
实验感想：
1）此次实验我学习了如何使用OvS命令让数据包打上Vlan标签，并学习了如何使用控制行实现流表下发。
2）通过进阶实验，我学习了如何使用python文件实现流表下发，并能在python文件中进行测试。编写python文件的过程中遇到不少bug，但通过不断尝试最终进行了解决，提升了我的问题解决能力及创新能力。
3）用VLAN技术可以设计广播域构成，交换机收到广播帧后，从而防止广播风暴
