mininet多数据中心带宽实验（2021.6.27）

2023-10-30 09:46:34

目的：创建多数据中心拓扑 iperf使用通过程序生成真实网络流量

1.mininet创建fattree拓扑：sudo mn --custom fattree.py --topo mytopo --controller=remote,ip=192.168.231.131,port=6653

from mininet.topo import Topo
from mininet.net import Mininet
from mininet.node import RemoteController,CPULimitedHost
from mininet.link import TCLink
from mininet.util import dumpNodeConnections

class MyTopo( Topo ):
    "Simple topology example."
    def __init__( self ):
        "Create custom topo."
        # Initialize topology
        Topo.__init__( self )
        L1 = 2
        L2 = L1 * 2 
        L3 = L2
        c = []
        a = []
        e = []  

        # add core ovs  
        for i in range( L1 ):
                sw = self.addSwitch( ‘c{}‘.format( i + 1 ) )
                c.append( sw )

        # add aggregation ovs
        for i in range( L2 ):
                sw = self.addSwitch( ‘a{}‘.format( L1 +i + 1 ) )
                a.append( sw )

        # add edge ovs
        for i in range( L3 ):
                sw = self.addSwitch( ‘e{}‘.format( L1 +L2 + i + 1 ) )
                e.append( sw )

        # add links between core and aggregation ovs
        for i in range( L1 ):
                sw1 = c[i]
                for sw2 in a[i/2::L1/2]:                    
                        self.addLink( sw2, sw1 )

        # add links between aggregation and edge ovs
        for i in range( 0, L2, 2 ):
                for sw1 in a[i:i+2]:
                    for sw2 in e[i:i+2]:
                        self.addLink( sw2, sw1 )

        #add hosts and its links with edge ovs
        count = 1
        for sw1 in e:
                for i in range(2):
                    host = self.addHost( ‘h{}‘.format( count ) )
                    self.addLink( sw1, host )
                    count += 1
topos = { ‘mytopo‘: ( lambda: MyTopo() ) }

2.开启ryu：sudo ryu-manager --verbose simple_switch_stp_13.py ofctl_rest.py rest_topology.py

注意！：这里为了防止广播风暴，使用了STP协议simple_switch_stp_13.py。

3.先pingall，打流。

4.测试h1与其它主机之间的带宽。

但是mininet里没有所有主机间的带宽测试，需要自定义命令去实现该功能。

5.流量随机模型：所有主机间的随机带宽测试

mininet自定义命令的步骤：

① mininet/net.py定义iperf_single()函数

在两个主机间iperf udp测试，并且在server端记录，实现iperf_single()函数

def iperf_single( self,hosts=None, udpBw=5, period=5, port=5001):
        """"""
        if not hosts:
            return
        else:
            assert len( hosts ) == 2
        client, server = hosts
        filename = client.name+‘.out‘
        filenameserver = server.name+‘.out‘
        delayname = client.name+‘-‘+server.name+‘.delay‘
        output( ‘***testing bandwidth between ‘ )
        output( "%s and %s\n" % ( client.name, server.name ) )
        iperfArgs = ‘iperf -u‘    
        print "****start server******"
        server.cmd( iperfArgs + ‘-s‘ + ‘ >> /home/zhao/log/‘ + ‘server-‘+filenameserver + ‘&‘)
        print "****start client******"
        client.cmd(iperfArgs + ‘-t ‘ + str(period) + ‘ -c ‘ + server.IP() + ‘ -b ‘+str(udpBw)+‘M‘+ ‘ >> /home/zhao/log/‘+ ‘client-‘ + filename +‘&‘)

②net.py中添加自定义的iperfmulti()函数

依次为每一台主机随机选择另一台主机作为iperf的服务器端，通过调用iperf_single，自身以客户端按照指定参数发送UDP流。

    def iperf_single( self,hosts=None, udpBw=‘10M‘, period=60, port=5001):

        

        if not hosts:

            return

        else:

            assert len( hosts ) == 2

        client, server = hosts

        filename = client.name[1:] + ‘.out‘

        output( ‘*** Iperf: testing bandwidth between ‘ )

        output( "%s and %s\n" % ( client.name, server.name ) )

        iperfArgs = ‘iperf -u ‘      

        bwArgs = ‘-b ‘ + udpBw + ‘ ‘   

        print "***start server***"

        server.cmd( iperfArgs + ‘-s -i 1‘ + ‘ > /home/zg/log/‘ + filename + ‘&‘)   

        print "***start client***"

        client.cmd(

            iperfArgs + ‘-t ‘+ str(period) + ‘ -c ‘ + server.IP() + ‘ ‘ + bwArgs

            +‘ > /home/zg/log/‘ + ‘client‘ + filename +‘&‘)

如图所示，其中目录需要是真实存在的路径

③mininet/cli.py中注册iperfmulti命令

解析用户输入的命令，net.py定义的iperfmulti命令需要在CLI类中注册。

def do_iperfmulti( self, line ):
           args=line.split()
        if len(args) == 1:
            udpBw = args[ 0 ]
            self.mn.iperfMulti(udpBw)
        elif len(args)== 2:
            udpBw = args[ 0 ]
            period = args[ 1 ]
            err = False
            self.mn.iperfMulti(udpBw,int(period))
        else:
            error(‘invalid number of args: iperfmulti udpBw \n‘ +‘udpBw examples: 1M\n‘)

④bin/mn中加入iperfmulti可执行命令

将iperfmulti加入到对应的列表中。

    def iperfMulti(self, bw, period=60):

        base_port = 5001

        server_list = []

        client_list = [h for h in self.hosts]

        host_list = []

        host_list = [h for h in self.hosts]

        cli_outs = []

        ser_outs = []

        _len = len(host_list)

        for i in xrange(0, _len):

            client = host_list[i]

            server = client

            while( server == client ):

                server = random.choice(host_list)

            server_list.append(server)

            self.iperf_single(hosts = [client, server], udpBw=bw, period= period, port=base_port)

            sleep(.05)

            base_port += 1

            sleep(period)

            print "test has done"