实验5：开源控制器实践——POX

1.基本要求
使用 tcpdump 验证Hub模块
h1 ping h2（h3和h2都能抓到包）

h1 ping h3（h3和h2都能抓到包）

验证Switch模块
h1 ping h2(只有h2抓包)

h1 ping h3(只有h3抓包)

L2_learning模块代码流程图

2.进阶要求
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

code

 from =  pox.core import core
 import pox.openflow.libopenflow_01 as of
 from pox.openflow.of_json import *

    def SendFlowInSingle3(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.openflow.addListenerByName("ConnectionUp", SendFlowInSingle3);

2.基于进阶1的代码，完成ODL实验的硬超时功能。


code

 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)

心得体会

1.本次实验难度较之前要大，理解PDF的内容需要花费一定的时间，而且初次遇到POX，不知道其功能作用，学习起来较有难度。
2.在学习l2_learning模块时，参考了同学的流程图，并加以理解，在做进阶实验时遇到的困难比较多，因为文档为全英文，观看起来比较困难。在进行ODL实验时，在运行SendFlowInSingle3和SendPoxHardTimeOut的顺序上也尝试了较多次，需要先运行pox模板SendFlowInSingle3，接着将SendFlowInSingle3中断掉，再运行SendPoxHardTimeOut，等待中断后，将SendPoxHardTimeOut断掉，接着再次运行SendFlowInSingle3，实现任务要求。