1
 2 #!/usr/bin/python
 3
 4 # 调用mininet的模块
 5
 6 from mininet.topo import Topo
 7
 8 from mininet.net import Mininet
 9
10 from mininet.node import CPULimitedHost
11
12 from mininet.link import TCLink
13
14 from mininet.util import dumpNodeConnections
15
16 from mininet.log import setLogLevel
17
18 # 创建一个基于Topo类的“单交换机拓扑”类
19
20 class SingleSwitchTopo(Topo):
21
22 "Single switch connected to n hosts."
23
24 # 定义构造函数（其中**opts代表的是关于网络一些选项的字典）
25
26 def __init__(self, n=2, **opts):
27
28 # 调用父类函数
29
30 Topo.__init__(self, **opts)
31
32 # 添加s1交换机
33
34 switch = self.addSwitch('s1')
35
36 for h in range(n):
37
38 #每个主机占50/n%的CPU
39
40 host = self.addHost('h%s' % (h + 1), cpu=.5/n)
41
42 #10 Mbps, 5ms 延迟, 0% 丢包, 1000 字节的大小
43
44 self.addLink(host, switch, bw=10, delay='5ms', loss=0, max_queue_size=1000, use_htb=True)
45
46
47
48 def perfTest():
49
50 "Create network and run simple performance test"
51
52 # 创建4个主机的单交换机拓扑
53
54 topo = SingleSwitchTopo(n=4)
55
56 # 调用Mininet（）的函数设置拓扑，主机，以及链路
57
58 net = Mininet(topo=topo,host=CPULimitedHost, link=TCLink)
59
60 net.start()
61
62 print "Dumping host connections"
63
64 dumpNodeConnections(net.hosts)
65
66 print "Testing network connectivity"
67
68 net.pingAll()
69
70 print "Testing bandwidth between h1 and h4"
71
72 h1, h4 = net.get('h1', 'h4')
73
74 net.iperf((h1, h4))
75
76 net.stop()
77
78
79
80 if __name__=='__main__':
81
82 setLogLevel('info')
83
84 perfTest()