实验5 开源控制器实践——POX

实验5 开源控制器实践——POX

基础实验

1. hub
   

分析：
由于在hub模式下，采取广播帧的模式，交换机每收到一帧，会向所有端口进行广播，因而h1发给h2的数据包在h3的端口也能监听到

2. switch
   

分析：
由于在自学习模式下，交换机会根据mac高速缓存信息进行发送数据包，因而在实验过程中，对于h1发给h2的数据包，h3只能捕捉到h1对h2的arp请求，并不能捕捉到数据包

3. 流程图
   

进阶实验

1. 自定义一个POX模块SendFlowInSingle3

from pox.core import core
import pox.openflow.libopenflow_01 as of

class SendFlowInSingle3(object):
    def __init__(self):
        core.openflow.addListeners(self)
    def _handle_ConnectionUp(self, event):
        msg = of.ofp_flow_mod()  
        msg.priority = 1
        msg.match.in_port = 1 
        msg.actions.append(of.ofp_action_output(port=2)) 
        msg.actions.append(of.ofp_action_output(port=3)) 
        event.connection.send(msg)

        msg = of.ofp_flow_mod()  
        msg.priority = 1
        msg.match.in_port = 2 
        msg.actions.append(of.ofp_action_output(port=1)) 
        msg.actions.append(of.ofp_action_output(port=3))  
        event.connection.send(msg)

        msg = of.ofp_flow_mod() 
        msg.priority = 1
        msg.match.in_port = 3  
        msg.actions.append(of.ofp_action_output(port=1))  
        msg.actions.append(of.ofp_action_output(port=2)) 
        event.connection.send(msg)

def launch():
    core.registerNew(SendFlowInSingle3)
    

结果：

2. 硬超时功能
   2.1 利用1编写的代码，手工开启、断开、再开启
   

流表查看：

2.2 直接运行SendPoxHardTimeOut

from pox.core import core
import pox.openflow.libopenflow_01 as of

class SendPoxHardTimeOut(object):
    def __init__(self):
        core.openflow.addListeners(self)
    def _handle_ConnectionUp(self, event):
	
	
        msg = of.ofp_flow_mod()  
        msg.priority = 2
        msg.match.in_port = 1 
        msg.hard_timeout = 10
        event.connection.send(msg)
        
        msg = of.ofp_flow_mod()  
        msg.priority = 1
        msg.match.in_port = 1 
        msg.actions.append(of.ofp_action_output(port=2)) 
        msg.actions.append(of.ofp_action_output(port=3)) 
        event.connection.send(msg)
        
        msg = of.ofp_flow_mod()  
        msg.priority = 2
        msg.match.in_port = 2 
        msg.hard_timeout = 10
        event.connection.send(msg)

        msg = of.ofp_flow_mod()  
        msg.priority = 1
        msg.match.in_port = 2 
        msg.actions.append(of.ofp_action_output(port=1)) 
        msg.actions.append(of.ofp_action_output(port=3))  
        event.connection.send(msg)
        
        msg = of.ofp_flow_mod()  
        msg.priority = 2
        msg.match.in_port = 3 
        msg.hard_timeout = 10
        event.connection.send(msg)
        
        msg = of.ofp_flow_mod() 
        msg.priority = 1
        msg.match.in_port = 3  
        msg.actions.append(of.ofp_action_output(port=1))  
        msg.actions.append(of.ofp_action_output(port=2)) 
        event.connection.send(msg)

def launch():
    core.registerNew(SendPoxHardTimeOut)

流表查看：

实验总结

本次实验主要学习POX控制器的使用方法，通过实验学习，我对比了集线器和交换机传输帧的区别，切实地感受到交换机自学习算法能够有效地减少广播风暴。并且，通过此次实验，我了解了如何通过编写代码实现硬实时功能、下发流表功能，颇有收获。