2019 SDN上机第1次作业

1.安装轻量级网络仿真工具Mininet

github上的Mininet源安装：

git clone git://github.com/mininet/mininet
cd mininet
./util/install.sh -a

2.用字符命令搭建如下拓扑，要求写出命令

命令行输入：

sudo mn --topo linear,3

命令行输入：

sudo mn --topo tree,fanout=3,depth=2

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。

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，h1h8，并且链路正确，请给出Mininet相关截图）

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         
        c = []
        a = []  

        # 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 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 hosts and its links with aggregation ovs
        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() ) }

命令行输入：

sudo mn --custom fattree.py --topo mytopo --switch ovsk,protocols=OpenFlow10