一、基礎(chǔ)要求

1、/home/k/032002225/lab2/目錄下執(zhí)行ovs-vsctl show命令、以及p0和p1連通性測試的執(zhí)行結(jié)果截圖；

2、 /home/k/032002225/lab2/目錄下開啟Mininet CLI并執(zhí)行pingall命令的截圖、上述目錄下查看OVS流表的命令結(jié)果截圖，wireshark抓包截圖，

二、進(jìn)階要求

使用Mininet，編寫Python代碼，生成（一）中的SDN拓?fù)洌⒃诖a中直接使用OVS命令，做到可以直接運(yùn)行Python程序完成和（一）相同的VLAN劃分。

python代碼：

`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='10.0.0.0/8')

info( '*** Adding controller\n' )
c0=net.addController(name='c0',
                  controller=Controller,
                  protocol='tcp',
                  port=6653)

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(s2, s1,3,3)
net.addLink(s1, h2,2,1)
net.addLink(s2, h4,2,1)
net.addLink(s2, h3,1,1)

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()`

直接運(yùn)行python代碼并pingall與抓包截圖：

三、個人總結(jié)

實(shí)驗的難度其實(shí)不大，照著老師給的PPT其實(shí)按步驟來做很快就完成了。但是主要的點(diǎn)在于理解那些語句是怎么劃分的流表，記住一些固定的語法格式。還有就是學(xué)會用wireshark來抓包。

實(shí)驗中的問題是：PPT中有些語句沒有表明在哪個地方輸入，這點(diǎn)請教了一些人再加上自己的摸索花費(fèi)了一些時間才解決。還有就是在直接用Python執(zhí)行代碼的時候，要先把上一個用命令行終端輸入“ovs-vsctl”命令開的那個表先關(guān)掉。最后一個問題是剛開始做的時候不知道關(guān)掉虛擬機(jī)會把虛擬空間關(guān)掉，后來又得重新做，花了一點(diǎn)時間。