1. Programming Assignment
Wang Zixiao
School of Computing
National University of Singapore
CS 4226: Internet Architecture

2. Overview: step 1
Build a virtual network with Mininet network emulation environment s1
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s

3. Mininet network Node Link Switch 20 Mb/s 10 Mb/s h1 h3 h2 h4 h5 h6 h7
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
Node
Link
Switch

4. Mininet network Host Machine Virtual Machine s1 s4 s2 s3 h1 h3 h2 h4
Virtua Network

5. Overview: step 2
Program the OpenFlow controller POX to implement three applications: Learning Switch, Firewall, VPN

6. Mininet network POX Host Machine Virtual Machine s1 s4 s2 s3 h1 h3 h2
Virtual Network

7. Learning Switch S1 Forward Table 20 Mb/s 10 Mb/s h1->h3 MAC Address
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
h1->h3
S1 Forward Table
MAC Address
Port

8. Learning Switch S1 Forward Table 20 Mb/s 10 Mb/s h1->h3 h1->h3
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
h1->h3
h1->h3
h1->h3
S1 Forward Table
MAC Address
Port
00:00:00:00:00:01 1

9. Learning Switch S1 Forward Table 20 Mb/s 10 Mb/s h3->h1
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
h3->h1
S1 Forward Table
MAC Address
Port
00:00:00:00:00:01 1
00:00:00:00:00:03 3

10. Firewall Block List: [10.0.0.1, 10.0.0.4, 80] 20 Mb/s 10 Mb/s
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
h1->h4:80

11. Firewall Block List: [10.0.0.1, 10.0.0.4, 80] 20 Mb/s 10 Mb/s
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
h1->h4:100

12. Virtual Private Network (VPN)s1
dpid:1 s4
dpid:4 s2
dpid:2 s3
dpid:3 h1 h3 h2 h4 h5 h6 h7
20 Mb/s
10 Mb/s
What is the sample space? 36 (i,j) pairs.
h1->h4
100 Mb/s
h1->h4
50 Mb/s

13. Priority Firewall VPN Learning Switch > >
What is the sample space? 36 (i,j) pairs.
VPN
>
Learning Switch

14. Submission File: mininetTopo.py, controller.py Comments
What is the sample space? 36 (i,j) pairs.
Comments
Report (1 page)

15. Demo Run mininetTopo.py, controller.py
Network Topology + Learning Switch: topology.in ping all hosts ( pingall command)
What is the sample space? 36 (i,j) pairs.
Firewall: polocy.in One host sends data to another on certain ports (iperf )
VPN: polocy.in Hosts in the same company Vs. Hosts from different companies

16. Preview Packet sent to controller “PacketIn” event fired
No flow table match
Compose and send message
Write flow table entry
Action
Flow table match
Second packet arrives at switch
Parse packet and execute control logic
First packet arrives at switch
Msg
Listener
Control Logic
Messager
POX
OpenFlow
OpenFlow
OpenFlow
PacketIn
Control Plane
Data Plane
OpenFlow
Switch
OpenFlow
Switch
Entry 1
Mininet
OpenFlow
Switch 1 2

17. Mininet
Creates a realistic network, running real kernel, switch and application code on a single machine
Interact with the network using Mininet Command Line Interface (CLI)
Support OpenFlow switches (OpenVSwitch)
Support custom topologies

18. Important classes and functions
Topo: the base class for Mininet topologies
addSwitch(): adds a switch to a topology and returns the switch name
addHost(): adds a host to a topology and returns the host name
addLink(): adds a bidirectional link to a topology

19. Important classes and functions
Mininet: the main class to create and manage a network
start(): starts your network
stop(): stops your network
pingAll(): tests connectivity by trying to have all nodes ping each other

21. Setup: Mininet Download Virtualbox ( Recommended)
Download Mininet Image ( FTP server)
What is the sample space? 36 (i,j) pairs.
Install the Mininet Appliance

22. Setup: POX Install Ubuntu (Recommended)
What is the sample space? 36 (i,j) pairs.
Checkout POX controller from github
Checkout and install POXDest (optional)

23. Test your code Check the topology using POXDesk Test learning switch
Test firewall
Test VPN