参照：基于Mininet测量路径的损耗率
还记不记得我们用python脚本写拓扑时，可以设置链路的损耗率，现在我们就要通过实验来测试这个损耗率。
实验介绍
在该环境下，h0向h1发送数据包，由于在mininet脚本中设置了连接损耗率，在传输过程中会丢失一些包，本次实验的目的是展示如何通过控制器计算路径损耗速率（h0-s0-s1-h1）。这里假设控制器预先知道网络拓扑，所以我没有显示发现网络的代码以及其他相关代码。控制器将向s0和s1发送flow_stats_request，当控制器接收到来自s0的response时，将特定流的数据包数保存在input_pkts中，当控制器接收到来自s1的response时，将接收到特定流的数据包数保存在output_pkts中，差值就是丢失的数据包数量。
搭建环境
1.写python脚本
- 在Mininet目录下新建文件mymininet.py。
touch test.pyvim test.py- 编辑文件mymininet.py，内容如下：
#!/usr/bin/python from mininet.net import Mininetfrom mininet.node import Nodefrom mininet.link import TCLinkfrom mininet.log import ?setLogLevel, infofrom threading import Timerfrom mininet.util import quietRunfrom time import sleep def myNet(cname=‘controller‘, cargs=‘-v ptcp:‘): ???"Create network from scratch using Open vSwitch." ???info( "*** Creating nodes\n" ) ???controller = Node( ‘c0‘, inNamespace=False ) ???switch = Node( ‘s0‘, inNamespace=False ) ???switch1 = Node( ‘s1‘, inNamespace=False ) ???h0 = Node( ‘h0‘ ) ???h1 = Node( ‘h1‘ ) ???????info( "*** Creating links\n" ) ???linkopts0=dict(bw=100, delay=‘1ms‘, loss=0) ???linkopts1=dict(bw=100, delay=‘1ms‘, loss=10) ???link0=TCLink( h0, switch, **linkopts0) ???link1 = TCLink( switch, switch1, **linkopts1) ????????link2 = TCLink( h1, switch1, **linkopts0) ???#print link0.intf1, link0.intf2 ???link0.intf2.setMAC("0:0:0:0:0:1") ???link1.intf1.setMAC("0:0:0:0:0:2") ???link1.intf2.setMAC("0:1:0:0:0:1") ????link2.intf2.setMAC("0:1:0:0:0:2") ????info( "*** Configuring hosts\n" ) ???h0.setIP( ‘192.168.123.1/24‘ ) ???h1.setIP( ‘192.168.123.2/24‘ ) ??????????info( "*** Starting network using Open vSwitch\n" ) ???switch.cmd( ‘ovs-vsctl del-br dp0‘ ) ???switch.cmd( ‘ovs-vsctl add-br dp0‘ ) ???switch1.cmd( ‘ovs-vsctl del-br dp1‘ ) ???switch1.cmd( ‘ovs-vsctl add-br dp1‘ ) ????controller.cmd( cname + ‘ ‘ + cargs + ‘&‘ ) ????????for intf in switch.intfs.values(): ???????print intf ???????print switch.cmd( ‘ovs-vsctl add-port dp0 %s‘ % intf ) ???for intf in switch1.intfs.values(): ???????print intf ???????print switch1.cmd( ‘ovs-vsctl add-port dp1 %s‘ % intf ) ??????# Note: controller and switch are in root namespace, and we ???# can connect via loopback interface ???switch.cmd( ‘ovs-vsctl set-controller dp0 tcp:10.0.0.13:6633‘ ) ???switch1.cmd( ‘ovs-vsctl set-controller dp1 tcp:10.0.0.13:6633‘ ) ?????info( ‘*** Waiting for switch to connect to controller‘ ) ???while ‘is_connected‘ not in quietRun( ‘ovs-vsctl show‘ ): ???????sleep( 1 ) ???????info( ‘.‘ ) ???info( ‘\n‘ ) ????#info( "*** Running test\n" ) ???h0.cmdPrint( ‘ping -Q 0x64 -c 20 ‘ + h1.IP() ) ???????sleep( 1 ) ????info( "*** Stopping network\n" ) ???controller.cmd( ‘kill %‘ + cname ) ???switch.cmd( ‘ovs-vsctl del-br dp0‘ ) ???switch.deleteIntfs() ???switch1.cmd( ‘ovs-vsctl del-br dp1‘ ) ???switch1.deleteIntfs() ???info( ‘\n‘ ) if __name__ == ‘__main__‘: ???setLogLevel( ‘info‘ ) ???info( ‘*** Scratch network demo (kernel datapath)\n‘ ) ???Mininet.init() ???myNet() ???2.写POX脚本
- 在POX目录下新建文件flow_stats.py。
- 编辑文件flow_stats.py，内容如下：
#This file is part of POX.## POX is free software: you can redistribute it and/or modify# it under the terms of the GNU General Public License as published by# the Free Software Foundation, either version 3 of the License, or# (at your option) any later version.## POX is distributed in the hope that it will be useful,# but WITHOUT ANY WARRANTY; without even the implied warranty of# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the# GNU General Public License for more details.## You should have received a copy of the GNU General Public License# along with POX. If not, see <http://www.gnu.org/licenses/>.# """This is a demonstration file created to show how to obtain flow and port statistics from OpenFlow 1.0-enabled switches. The flowstatistics handler contains a summary of web-only traffic.""" # standard includesfrom pox.core import corefrom pox.lib.util import dpidToStrimport pox.openflow.libopenflow_01 as offrom pox.lib.addresses import IPAddr, EthAddr # include as part of the betta branchfrom pox.openflow.of_json import *from pox.lib.recoco import Timerimport time log = core.getLogger() src_dpid = 0dst_dpid = 0input_pkts = 0output_pkts = 0 def getTheTime(): ?#fuction to create a timestamp ?flock = time.localtime() ?then = "[%s-%s-%s" %(str(flock.tm_year),str(flock.tm_mon),str(flock.tm_mday)) ???if int(flock.tm_hour)<10: ???hrs = "0%s" % (str(flock.tm_hour)) ?else: ???hrs = str(flock.tm_hour) ?if int(flock.tm_min)<10: ???mins = "0%s" % (str(flock.tm_min)) ?else: ???mins = str(flock.tm_min) ?if int(flock.tm_sec)<10: ???secs = "0%s" % (str(flock.tm_sec)) ?else: ???secs = str(flock.tm_sec) ?then +="]%s.%s.%s" % (hrs,mins,secs) ?return then # handler for timer function that sends the requests to all the# switches connected to the controller.def _timer_func (): ?for connection in core.openflow._connections.values(): ???connection.send(of.ofp_stats_request(body=of.ofp_flow_stats_request())) ???connection.send(of.ofp_stats_request(body=of.ofp_port_stats_request())) ?log.debug("Sent %i flow/port stats request(s)", len(core.openflow._connections)) # handler to display flow statistics received in JSON format# structure of event.stats is defined by ofp_flow_stats()def _handle_flowstats_received (event): ??#stats = flow_stats_to_list(event.stats) ??#log.debug("FlowStatsReceived from %s: %s", dpidToStr(event.connection.dpid), stats) ??global src_dpid, dst_dpid, input_pkts, output_pkts ??#print "src_dpid=", dpidToStr(src_dpid), "dst_dpid=", dpidToStr(dst_dpid) ??for f in event.stats: ????if f.match.dl_type==0x0800 and f.match.nw_dst==IPAddr("192.168.123.2") and f.match.nw_tos==0x64 and event.connection.dpid==src_dpid: ???????#print "input: ", f.byte_count, f.packet_count ??????input_pkts = f.packet_count ????if f.match.dl_type==0x0800 and f.match.nw_dst==IPAddr("192.168.123.2") and f.match.nw_tos==0x64 and event.connection.dpid==dst_dpid: ??????#print "output: ", f.byte_count, f.packet_count ????????output_pkts = f.packet_count ??????if input_pkts !=0: ????????print getTheTime(), "Path Loss Rate =", (input_pkts-output_pkts)*1.0/input_pkts*100, "%" # handler to display port statistics received in JSON formatdef _handle_portstats_received (event): ??#print "\n<<<STATS-REPLY: Return PORT stats for Switch", event.connection.dpid,"at ",getTheTime() ??#for f in event.stats: ?????#if int(f.port_no)<65534: ???????#print " ??PortNo:", f.port_no, " Fwd‘s Pkts:", f.tx_packets, " Fwd‘s Bytes:", f.tx_bytes, " Rc‘d Pkts:", f.rx_packets, " Rc‘s Bytes:", f.rx_bytes ???????#print " ??PortNo:", f.port_no, ?" TxDrop:", f.tx_dropped, " RxDrop:", f.rx_dropped, " TxErr:", f.tx_errors, " RxErr:", f.rx_errors, " CRC:", f.rx_crc_err, " Coll:", f.collisions ??stats = flow_stats_to_list(event.stats) ?log.debug("PortStatsReceived from %s: %s", dpidToStr(event.connection.dpid), stats) def _handle_ConnectionUp (event): ?global src_dpid, dst_dpid ?print "ConnectionUp: ", dpidToStr(event.connection.dpid) ?for m in event.connection.features.ports: ???if m.name == "s0-eth0": ?????src_dpid = event.connection.dpid ???elif m.name == "s1-eth0": ?????dst_dpid = event.connection.dpid ??msg = of.ofp_flow_mod() ?msg.priority =1 ?msg.idle_timeout = 0 ?msg.match.in_port =1 ?msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL)) ?event.connection.send(msg) ??msg = of.ofp_flow_mod() ?msg.priority =1 ?msg.idle_timeout = 0 ?msg.match.in_port =2 ?msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL)) ?event.connection.send(msg) ??msg = of.ofp_flow_mod() ?msg.priority =10 ?msg.idle_timeout = 0 ?msg.hard_timeout = 0 ?msg.match.dl_type = 0x0800 ?msg.match.nw_tos = 0x64 ?msg.match.in_port=1 ?msg.match.nw_dst = "192.168.123.2" ?msg.actions.append(of.ofp_action_output(port = 2)) ?event.connection.send(msg) ??msg = of.ofp_flow_mod() ?msg.priority =10 ?msg.idle_timeout = 0 ?msg.hard_timeout = 0 ?msg.match.dl_type = 0x0800 ?msg.match.nw_tos = 0x64 ?msg.match.nw_dst = "192.168.123.1" ?msg.actions.append(of.ofp_action_output(port = 1)) ?event.connection.send(msg) ???# main functiont to launch the moduledef launch (): ?# attach handsers to listners ?core.openflow.addListenerByName("FlowStatsReceived", ????_handle_flowstats_received) ??core.openflow.addListenerByName("PortStatsReceived", ????_handle_portstats_received) ??core.openflow.addListenerByName("ConnectionUp", _handle_ConnectionUp) ??# timer set to execute every five seconds ?Timer(1, _timer_func, recurring=True) ?3.运行脚本flow_stats.py。
/pox.py flow_stats4.运行脚本mymininet.py。
chmod +x mymininet.py./mymininet.py控制器连不上去，不知道为什么。。。
mininet实验 测量路径损耗率
原文地址：https://www.cnblogs.com/031602523liu/p/8986607.html