2019 SDN大作业--数据中心类型网络拓扑的搭建与连接
贡献比例
| 学号 | 比例 |
|---|---|
| 031702345 | 28% |
| 031702311 | 18% |
| 031702428 | 18% |
| 031702309 | 18% |
| 131700101 | 18% |
实验概述
使用两个互为备份的中心交换机
连接两两互为备份的共计四个交换机
下接四组各连有两台主机的交换机
作为数据中心类型网络拓扑的一个小型实现
上、中、下层均可以扩展来实现对更多网络主机的支持
实现在网络中心区域防止单个设备故障所引发的网络中断
实验拓扑
实验拓扑图如下
建立实验网络
建立流程如下
1.先打开OpenDayLigtht作为remote控制器,否则先运行mininet则不能连接到控制器
2.运行mininet建立拓扑结构，运行代码如sudo mn --custom datacenter.py --topo mytopo --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13
3.打开http://127.0.0.1:8181/index.html#/topology来查看拓扑
4.在mininet中输入net来获取网络接口信息，作为下发流表的依据
mininet的拓扑结构的Python代码如下：
#!/usr/bin/python
#创建网络拓扑
"""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() ) }
OpenDayLigtht的远程控制器代码如下：
先在控制台中运行./karaf打开容器
接着按照顺序安装feature如下
install odl-restconf install odl-l2switch-switch-ui install odl-openflowplugin-all install odl-mdsal-apidocs install odl-dlux-core install odl-dlux-node install odl-dlux-yangui
在退出前执行logout退出
运行完后在YangUI中可见拓扑结构如图
节点编号与节点名称关系如下表（加载原因未能加载出全部）
下发初始流表连接链路
1.清空所有流表项
sudo ovs-ofctl -O Openflow13 del-flows c1 sudo ovs-ofctl -O Openflow13 del-flows c2 sudo ovs-ofctl -O Openflow13 del-flows a3 sudo ovs-ofctl -O Openflow13 del-flows a4 sudo ovs-ofctl -O Openflow13 del-flows a5 sudo ovs-ofctl -O Openflow13 del-flows a6 sudo ovs-ofctl -O Openflow13 del-flows e7 sudo ovs-ofctl -O Openflow13 del-flows e8 sudo ovs-ofctl -O Openflow13 del-flows e9 sudo ovs-ofctl -O Openflow13 del-flows e10
2.下发下层流表
#e7 sudo ovs-ofctl -O OpenFlow13 add-flow e7 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e7 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e7 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e7 priority=2,in_port=4,actions=output:1,output:2,output:3 #e8 sudo ovs-ofctl -O OpenFlow13 add-flow e8 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e8 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e8 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e8 priority=2,in_port=4,actions=output:1,output:2,output:3 #e9 sudo ovs-ofctl -O OpenFlow13 add-flow e9 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e9 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e9 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e9 priority=2,in_port=4,actions=output:1,output:2,output:3 #e10 sudo ovs-ofctl -O OpenFlow13 add-flow e10 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e10 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e10 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow e10 priority=2,in_port=4,actions=output:1,output:2,output:3
3.下发中层流表
#a3 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=4,actions=output:1,output:2,output:3 #a4 sudo ovs-ofctl -O OpenFlow13 add-flow a4 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a4 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a4 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a4 priority=2,in_port=4,actions=output:1,output:2,output:3 #a5 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=4,actions=output:1,output:2,output:3 #a6 sudo ovs-ofctl -O OpenFlow13 add-flow a6 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a6 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a6 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a6 priority=2,in_port=4,actions=output:1,output:2,output:3
4.下发上层流表
#c1 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=3,actions=output:1,output:2 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=4,actions=output:1,output:2 #c2 sudo ovs-ofctl -O OpenFlow13 add-flow c2 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c2 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c2 priority=2,in_port=3,actions=output:1,output:2 sudo ovs-ofctl -O OpenFlow13 add-flow c2 priority=2,in_port=4,actions=output:1,output:2
5.把上述代码封装入shell文件中可以实现一键下发和清空流表
测试链路可用性
1.在mininet中运行pingall命令
说明链路已经连接成功
2.在OpenDayLigtht拓扑图中可以清晰地看到每一个客户端
Iperf链路性能测试
h1连接h2测试:
可以看到带宽为9.92Gbits/sec
h1连接h3测试:
可以看到带宽为2.41Gbits/sec
h1连接h8测试:
可以看到带宽为122Mbits/sec
结论是随着跨交换机网络的转发，性能随着跨交换机网络而减弱，解决方法是用分时间片的方法来负载均衡。
负载均衡的实现
通过将某段时间流表设置成c1,a3,a5一组和c2,a4,a6一组来达到交换机的负载均衡，以提高性能。
负载均衡后再次执行链路性能测试
h1连接h2因为没有链路变化所以带宽基本不变
h1连接h3可以看到带宽从2.41Gbit/sec提高到了3.87Gbit/sec
h1连接h8可以看到带宽从122Mbit/sec提升到了292Mbit/sec
成组打开并关闭代码：
import os
import time
def runteam1():
os.system("./addt1.sh")
time.sleep(1)
os.system("./delt2.sh")
return 1;
def runteam2():
os.system("./addt2.sh")
time.sleep(1)
os.system("./delt1.sh")
return 1;
os.system("./delflows.sh")
os.system("./inite.sh")
while(True):
runteam1()
runteam2()
addt1.sh代码：
#c1 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=3,actions=output:1,output:2 sudo ovs-ofctl -O OpenFlow13 add-flow c1 priority=2,in_port=4,actions=output:1,output:2 #a3 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a3 priority=2,in_port=4,actions=output:1,output:2,output:3 #a5 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=1,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=2,actions=output:3,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=3,actions=output:1,output:2,output:4 sudo ovs-ofctl -O OpenFlow13 add-flow a5 priority=2,in_port=4,actions=output:1,output:2,output:3
delt1.sh代码：
sudo ovs-ofctl -O Openflow13 del-flows c1 sudo ovs-ofctl -O Openflow13 del-flows a3 sudo ovs-ofctl -O Openflow13 del-flows a5
addt2.sh、delt2.sh、inite.sh、delflows.sh的代码和上述示例十分接近，故不在赘述
本次实验因为是在本机进行，所以使用的是ovs-ofctl命令，若要进行远程的流表的下发，则需要使用Restful接口远程下发流表，下发内容与以上近似。
实验总结
经过本次实验，对OpenFlow、Mininet、OpenDayLight、OVS控制器等有了更加深入的理解，对软件定义网络也更加熟悉和清晰。
代码链接
https://github.com/opsiff/SDNExample
来源：https://www.cnblogs.com/phd1999/p/12154363.html