令狐_JackieHao的博客：Mininet多数据中心网络拓扑流量带宽实验

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令狐_JackieHao的博客：Mininet多数据中心网络拓扑流量带宽实验

作者：[db:作者] 时间：2021-06-27 17:40

任务目的

1、通过Mininet模拟搭建基于不同数据中心的网络拓扑； 2、掌握多数据中心网络拓扑的构建； 3、熟悉网络性能测试工具Iperf，根据实验测试SDN网络的性能； 4、通过程序生成真实网络流量。

任务环境

设备名称	软件环境	硬件环境
主机	Mininet_2.2.0_desktop_cv1.1	CPU：1核内存2G磁盘：20G

注：系统默认的账户为：管理员权限用户名：root，密码：root@openlab；普通用户用户名：openlab，密码：user@openlab。

实验步骤

一、实现iperfmulti功能生成多客户端随机产生UDP流量

步骤1 登录Mininet所在虚机，在Mininet目录下mininet/net.py文件中定义iperf_single()函数

在两个主机间进行iperf udp测试，并且在server端记录，实现iperf_single函数：

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

??????"""Run?iperf?between?two?hosts?using?UDP.

????????hosts:?list?of?hosts;?if?None,?uses?opposite?hosts
????????returns:?results?two-element?array?of?server?and?client?speeds"""

??????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/sdnlab/log/'?+?filename?+?'&')

??????print?"***start?client***"

??????client.cmd(

????????iperfArgs?+?'-t?'+?str(period)?+?'?-c?'?+?server.IP()?+?'?'?+?bwArgs

????????+'?>?/home/sdnlab/log/'?+?'client'?+?filename?+'&')

步骤2 net.py中添加自定义命令iperfmulti() 函数

为mininet添加自定义命令iperfmulti，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,自身以客户端身份按照指定参数发送UDP流，服务器生成的报告以重定向的方式输出到文件中，使用iperfmulti命令，主机随机地向另一台主机发起一条恒定带宽的UDP数据流。

?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"

步骤3 mininet/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类中注册这条自定义命令。

def?do_iperfmulti(?self,?line?):
????????"""Multi?iperf?UDP?test?between?nodes"""
????????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,?float(period))
????????else:
????????????error('invalid?number?of?args:?iperfmulti?udpBw?period\n'?+
???????????????????'udpBw?examples:?1M?120\n')

步骤4 bin/mn中加入iperfmulti可执行命令

将iperfmulti加入到对应的列表中。

ALTSPELLING?=?{?'pingall':?'pingAll',?'pingpair':?'pingPair',

????????'iperfudp':?'iperfUdp','iperfmulti':'iperfMulti'?}

步骤5 重新编译mininet

进入mininet/util目录，重新编译安装mininet。

#~/mininet/util/install.sh -n

步骤6 验证iperfmulti是否成功

重新创建网络，如mn，输入iperf，可用table补全iperfmulti，从而可使用iperfmulti进行流量随机模型的测试：

二、多数据中心拓扑创建脚本编写

步骤1 通过python脚本自定义拓扑，创建包含两个数据中心的网络拓扑：

#?cd?custom
#?vi?fattree.py


#!/usr/bin/python
"""Custom?topology?example
Adding?the?'topos'?dict?with?a?key/value?pair?to?generate?our?newly?defined
topology?enables?one?to?pass?in?'--topo=mytopo'?from?the?command?line.
"""
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,?bw=10,?delay='5ms',?loss=10,?max_queue_size=1000,?use_htb=True)
????????????????????????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()?)?}