使用环境：Windows7（32bit）, Oracle VM VirtualBox;
工具：mininet-2.2.2-170321-ubuntu-14.04.4-server-i386, pox controller, putty, Xming；
步骤：
1. Put the ddos.py and ddos_printer.py in ext folder under POX folder
2. Run the topology using Xming open the ddos_test.mn file in putty using this command:
3. cd mininet/examples
4. sudo ./miniedit.py
5. open the ddos_test.mn file in Xming
6. On new terminal window Run the controller using this command.
7. cd pox
8. ./pox.py forwarding.l3_learning ddos
9. Open the host7 terminal in the mininet topology and run the ddos_printer.py script using this command: sudo python ddos_printer.py
