实验5：开源控制器实践——POX

一、实验目的
1.能够理解 POX 控制器的工作原理；
2.通过验证POX的forwarding.hub和forwarding.l2_learning模块，初步掌握POX控制器的使用方法；
3.能够运用 POX控制器编写自定义网络应用程序，进一步熟悉POX控制器流表下发的方法。
二、实验环境
Ubuntu 20.04 Desktop amd64

三、实验要求
（一）基本要求
Hub模块
h1 ping h2

h1 ping h3

l2_learning 模块

h1 ping h2

h1 ping h3

L2_learning模块代码流程图

(二)进阶
1.重新搭建（一）的拓扑，此时交换机内无流表规则，拓扑内主机互不相通；编写Python程序自定义一个POX模块SendFlowInSingle3，并且将拓扑连接至SendFlowInSingle3（默认端口6633），实现向s1发送流表规则使得所有主机两两互通

2.1 基于进阶1的代码，完成ODL实验的硬超时功能。（先运行SendFlowSingle3，先通再断再恢复）

2.2 基于进阶1的代码，完成ODL实验的硬超时功能。（直接运行SendPoxHardTimeOut，先断后通，能验证流表项生效即可）

SendFlowInSingle3代码

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 = of.OFPP_ALL))
        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 = of.OFPP_ALL))
        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 = of.OFPP_ALL))
        event.connection.send(msg)


def launch ():
	core.registerNew(SendFlowInSingle3)

SendPoxHardTimeOut代码

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 = 3
        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 = of.OFPP_ALL)) 
        event.connection.send(msg)

        
        msg = of.ofp_flow_mod()  
        msg.priority = 3
        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 = of.OFPP_ALL))
        event.connection.send(msg)

def launch():
    core.registerNew(SendPoxHardTimeOut)