2019 SDN上机第1次作业

1. 安装轻量级网络仿真工具Mininet

安装步骤

• sudo git clone http://www.github.com/mininet/mininet
  

• sudo ./install.sh -a
  

2. 用字符命令搭建拓扑

线性拓扑

命令：sudo mn --topo linear,3

树形拓扑

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

利用可视化工具搭建拓扑

• 拓扑搭建
  

• net命令查看
  

• 运行Xterm h1,h2,h3,分别使用ifconfig
  

利用Python脚本完成Fat-tree型的拓扑

• 运行结果
  

• 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 ):

    def __init__( self ):
        "Create custom topo."
 
        # Initialize topology
        Topo.__init__( self )
        L1 = 2
        L2 = 4
        c = []
        e = []
          
        # add core ovs  
        for i in range( L1 ):
                sw = self.addSwitch( 's{}'.format( i + 1 ) )
                c.append( sw )
    
        # add edge ovs
        for i in range( L2 ):
                sw = self.addSwitch( 's{}'.format( L1 + i + 1 ) )
                e.append( sw )
 
        # add links between core and edge ovs
        for i in range( L1 ):
                sw1 = c[i]
                for sw2 in e:
			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() ) }