2019 SDN上机第一次作业

1.安装轻量级网络仿真工具Mininet

打开终端，依次执行以下命令完成安装过程：

从Github上下载最新源码：

**```git clone https://github.com/mininet/mininet.git

![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101214750039-1989443183.png)

###可以查看安装时可选择的mininet版本
**```cd mininet
```**
**```git tag
```**
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101215041516-1409924063.png)

###进入mininet/util/目录下进行安装
**```cd mininet/util
```**
**```
./install.sh```**
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101215200484-622289294.png)

###安装成功
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101215225820-819830831.png)

###安装成功后进行最小拓扑测试，发现提示未找到ifconfig，需要安装net-tools
**```sudo apt install net-tools
```**
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101215758633-1923254423.png)
#2.用字符命令搭建如下拓扑，要求写出命令
##1、搭建如下拓扑
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101221724687-1066015049.png)

**命令：```sudo mn --topo linear,3
```**
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101221833835-1549727776.png)

##2、搭建如下拓扑
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101221907229-866690733.png)

**命令：```sudo mn --topo tree,fanout=3,depth=2
```**
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191101222009339-966031203.png)

#3.利用可视化工具搭建如下拓扑，并要求支持OpenFlow 1.0 1.1 1.2 1.3，设置h1（10.0.0.10）、h2（10.0.0.11）、h3（10.0.0.12），拓扑搭建完成后使用命令验证主机ip，查看拓扑端口连接情况。
##1.利用可视化工具搭建拓扑
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103212636566-1854630464.png)

##2.搭建完成执行左下角RUN按钮，并输入 net 命令查看拓扑端口连接情况
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103212801710-694132735.png)

##3.分别验证h1,h2,h3主机IP
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103212914607-1858816282.png)
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103212927281-1713709191.png)
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103212936781-1889498808.png)

#4.利用Python脚本完成如下图所示的一个Fat-tree型的拓扑（交换机和主机名需与图中一致，即s1~s6，h1~h8，并且链路正确，请给出Mininet相关截图）
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103224343866-209663776.png)

##1.python脚本代码

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."

    Topo.__init__( self )
    L1 = 2
    L2 = L1 * 2 
    L3 = L2
    c = []
    a = []
    e = []
       
    for i in range( L1 ):
            sw = self.addSwitch( 's{}'.format( i + 1 ) )
            c.append( sw )

    for i in range( L2 ):
            sw = self.addSwitch( 's{}'.format( L1 + i + 1 ) )
            a.append( sw )

    for i in range( L1 ):
            sw1 = c[i]
            for sw2 in a[i/2::L1/2]:
                    self.addLink( sw2, sw1 )

    count = 1
    for sw1 in a:
            for i in range(2):
                host = self.addHost( 'h{}'.format( count ) )
                self.addLink( sw1, host )
                count += 1

topos = { 'mytopo': ( lambda: MyTopo() ) }

##2.运行python脚本
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103224453425-1894431883.png)

##3.输入 net 命令查看拓扑端口连接情况
![](https://img2018.cnblogs.com/blog/1798373/201911/1798373-20191103224611348-89548135.png)