实验2:Open vSwitch虚拟交换机实践
一、实验目的
1.能够对Open vSwitch进行基本操作;
2.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;
3.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
1.ovs-vsctl基础操作实践:创建OVS交换机,以ovs-xxxxxxxxx命名,其中xxxxxxxxx为本人学号。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;为了避免网络接口上的地址和本机已有网络地址冲突,需要创建虚拟网络空间(参考命令netns)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190.168.1.100、192.168.1.101,子网掩码为255.255.255.0;最后测试p0和p1的连通性。
2.使用Mininet搭建的SDN拓扑,如下图所示,要求支持OpenFlow 1.3协议,主机名、交换机名以及端口对应正确。
3.通过命令行终端输入“ovs-ofctl”命令,直接在s1和s2上添加流表,划分出所要求的VLAN。
VLAN_ID Hosts
0 h1 h3
1 h2 h4
4.主机连通性要求:
h1 – h3互通
h2 – h4互通
其余主机不通
(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。
(三)实验报告
ovs交换机的创建以及配置:
212106662.py代码:
from mininet.topo import Topo
class MyTopo(Topo):
def __init__(self):
# initilaize topology
Topo. __init__(self)
# add hosts
h1 = self.addHost('h1')
h2 = self.addHost('h2')
h3 = self.addHost('h3')
h4 = self.addHost('h4')
# add switches
s1 = self.addSwitch('s1')
s2 = self.addSwitch('s2')
# add links
self.addLink(h1, s1, 1, 1)
self.addLink(h2, s1, 1, 2)
self.addLink(h3, s2, 1, 1)
self.addLink(h4, s2, 1, 2)
self.addLink(s1, s2, 3, 3)
topos = {'mytopo': (lambda: MyTopo())}
s1,s2下发流表:
开启Wireshark抓包:
运行测试连通性:
进阶部分:
212106662-2.py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( '192.168.123.3/24' )
h4.setIP( '192.168.124.3/24' )
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()
运行结果:
个人总结:
这次作业在ovs交换机创建以及配置部分依照ppt学习,还算顺利,在第二部分编写完212106662.py代码后运行,命令行界面总是弹出s1不是根桥,才发现还需要再开启一个命令行终端才可以运行编写的代码,进阶部分需要将ovs-ofctl的代码编写到python中,在代码编写过程与同学交流互助,还需要加强python代码的编写能力,不断提升。