Python辅导 | Final Project: Implementing a Simple Router


Final Project: Implementing a Simple Router
In the previous lab you implemented a simple firewall that allowed ARP and TCP packets, but blocked all other
packets. For your final project, you will be expanding on this to implement routing between devices on different
subnets, and implementing firewalls for certain subnets. The idea is to simulate an actual production network.
You will be using ideas from Lab 1 to help construct the mininet topology, and ideas from Lab 3 to implement
the rules allowing for traffic to flow through your network. Please refer back to those Labs for guidance on how
to complete this assignment.
For this lab, we will be constructing a network for a small company. The company has a 3-floor building, with
each floor having its own switch and subnet. Additionally, we have a switch and subnet for all the servers in the
data center, and a core switch connecting everything together.
Your device’s roles and IP addresses are as follows:
Device Mininet Name IP Address Description
Floor 1 Host h1 A computer on floor 1 of the company.
Floor 2 Host h2 A computer on floor 2 of the company.
Floor 3 Host h3 A computer on floor 3 of the company.
Untrusted Host h4 A computer outside our network. We treat this
computer as a potential hacker.
Server h5 A server used by our internal hosts.
The topology will look as follows:
Your goal will be to allow traffic to be transmitted between all the hosts. In this assignment, you will be allowed
(and encouraged) to flood all non-IP traffic in the same method that you did in Lab 3 (using a destination port of
of.OFPP_FLOOD). However, you will need to specify specific ports for all IP traffic. You may do this however
you choose– however, you may find it easiest to determine the correct destination port by using the destination
IP address and source IP address, as well as the source port on the switch that the packet originated from.
Additional information has been given to you in the do_final() function to allow you to make these decisions.
Please see the comments in the provided code for guidance.
Additionally, to protect our servers from the untrusted Internet, we will be blocking all IP traffic from the
Untrusted Host to the Server. To block the Internet from discovering our internal IP addresses, we will also
block all ICMP traffic from the Untrusted Host to anywhere internally.
You will be required to demonstrate your project to the TAs. You will need to explain how you implemented the
various requirements and show that they work properly. If you need help figuring out how to do this, look back
to previous assignments and see how you tested them.
Provided Code:
Available in a ZIP file here.
We have provided you with starter code (skeleton files) to get you started on this assignment. The controller
file ( needs to be placed in ~/pox/pox/misc, and the mininet file ( should be
placed in your home directory (~). This time, you will need to modify both files to meet the lab requirements.
You will be using slightly different commands to create the Hosts and Links in the Mininet file to give you more
information to make decisions within the Controller file. Additionally, you will notice that you have additional
information provided in the do_final function. This is documented in the comments within the files.
Summary of Goals:
– Create a Mininet Topology (See Lab 1 for help) to represent the above topology.
– Create a Pox controller (See Lab 3 for help) with the following features:
– All hosts able to communicate, EXCEPT:
– Untrusted Host cannot send ICMP traffic to Host 1, Host 2, Host 3, or the Server.
– Untrusted Host cannot send any IP traffic to the Server.
You may test with ping commands, xterm windows, and observing packets with Wireshark inside your VM.
Please have a plan in place to show you have implemented all the requirements during your demonstration to
the TAs.
Grading Rubric:
Total: 100 points
Submit both the code and PDF report.
30 points: Mininet Topology
10: Devices successfully created.
10: Links successfully created.
10: IP addresses correct.
50 points: Pox Controller
25: All hosts can communicate.
15 point deduction if rules not installed in flow table.
20 point deduction if IP traffic is implemented using OFPP_FLOOD.
15: Untrusted Host cannot send ICMP traffic to Host 1, Host 2, Host 3, Server
10 point deduction if Untrusted Host cannot send ANY traffic to these hosts.
10: Untrusted Host cannot send any IP traffic to Server
20 points: Demonstration
Demo: You have 2 options for Demoing this assignment:
– 1. Demo to TA during lab section. You must show the TA that all the requirements for the assignment
are met.
– 2. Submit PDF report. You must include screenshots proving your code works. These screenshots
must come from your own code. This will be tested, and submitting screenshots of someone else’s
code can be considered an academic integrity violation.
Note that for the demo, we will *not* be telling you what commands to run to verify the assignment goals are
met. Figuring out how to prove your work is a part of this assignment.
Partial credit may be awarded for incomplete assignments based upon demonstration and explanations as to
why something may not be functioning properly.