COS-597E Assignments

Programming Assignments

• Assignment 1 (due 5pm Tuesday September 17, 2013):

  In this assignment, you will learn the basics of running Mininet in a VirtualBox virtual machine.

  First, install Virtual Box on your computer. Then, download and install the custom virtual machine for the course. (Do not use the VM referenced at the OpenFlow Tutorial Web site. Our custom VM works on a wider variety of platforms, and has software installed that you'll need on future assignments.) See the video instructions.

  To install the VM, start VirtualBox, and then select File>Import Appliance and select the downloaded ova file. Then, press the Import button.

  Then, follow the instructions for parts 1 through 4 of the OpenFlow Tutorial.

  • When following the instructions for "Set Up Network Access" (in Settings>Network>Adapter2) you will create a host-only interface for accessing your VM by SSH. Make sure that you select "Cable Connected" under "Advanced", while your machine is powered off, to ensure that this interface is "plugged in". (If your attempt to assign the interface an IP address (using dhclient) fails, check that your host-only interface has the "Cable Connected" -- again, while the VM is powered down.)
  • OS X Mountain Lion users: To enable X11 forwarding through OS X native terminal, you must install XQuartz, which isn't shipped with the OS anymore.
  • The instructions in Section 4.8 are incorrect, replace "$ sudo mn --topo single,3 --mac --controller remote --switch user" with "$ sudo mn --topo single,3 --mac".

  You may also find the MiniNet Sample Workflow for more details.

  You do not need to submit any written materials for this assignment.

• Assignment 2 (due 5pm Tuesday October 1, 2013):

  In this assignment, you will learn some basic SDN programming on the Ryu controller platform. Complete the Ryu Tutorial, using your existing VM from assignment 1 rather than installing a new VM.

  • Modify the simple MAC-learning switch to include logic blocking IP traffic between host 2 and host 3.
  • Extend this program to count all traffic going to or leaving host 1. Note that it is not sufficient to set up a counter and increment it in _packet_in_handler, because _packet_in_handler is only called when a packet arrives at the controller (i.e., for the first packet of a given flow).

  You could support the traffic monitoring in several ways. The most elegant way is for your program to send the switch a statistics request to read the counters associated with all rules forwarding to/from host 1 (e.g., using Ryu's get_flow_stats method to send a request, and creating a handler that both processes the response and triggers another stats call to occur after some time elapses). Note: simple_switch.py sets both hard and soft timeouts to 0 (meaning the rule never expires), so you don't need to worry about handling flow-deletion messages. However, you may use a simpler approach where you install rules for host 1 with a hard timeout, so that the rules expire periodically and trigger flow-deletion messages that contain the counter values for the expired rules. Then, you could set up a handler to process these flow-deletion messages. Be careful not to count the traffic multiple times (e.g., at each hop in the path to/from host 1)!

  You may find this list of OpenFlow 1.0 messages helpful. Note that some of the documentation is inconsistent (e.g., using "eth_src" and "eth_dst" for MAC addresses, rather than the "dl_src" and "dl_dst" fields that Ryu actually uses in its API for OpenFlow 1.0).

  You can submit your code here.

• Assignment 3 (due 5pm Friday October 11, 2013):

  In this assignment, you will learn some basic SDN programming on the Pyretic platform created here at Princeton, using the same VM from assignment 1.

  1. Read the Pyretic Documentation (don't worry it's short).

  2. Update your pyretic repo (from inside the VM)

      $ cd ~/pyretic
      $ git pull
      $ git checkout tester
      $ sudo pip install ipaddr
     

  3. Implement a simple mac learning module

  4. Write a simple firewalling module that blocks traffic between hosts 2 and 3

  5. Write a simple monitoring module that counts all packets going to or leaving host 1

  6. Write a module that imports each of the above and does firewalling and then mac learning while at the same time monitoring. Write two versions of this module: (i) monitoring all traffic, whether or not the firewall drops the traffic and (ii) monitor only the traffic that successfully passes through the firewall

  You can submit your code here.

Last updated: Thu Oct 10 15:40:40 -0400 2013