COSC 331




Fall 2017



0 Directions


This is a take home nal. You will need to turn the nal exam in between 12/12/17, Tuesday 8:00am to 10:30am in person. If you do not turn your nal exam in by 10:30am you will receive a 0 for the nal exam.


Please complete each question. The questions with be graded to a high standard; so grammar, logic, and understanding of the material are all taken into account. I expect a large amount of background research, good logical arguments, and very thorough analysis of the questions. Your answers should be complete and at a junior/senior in college level. Lack of sources will cause a substantial loss of points so don't make assertions that are not backed by facts and don't use others work without giving them credit. You can just copy paste web links and write book titles/page numbers (no formal citing needed). You should do this alone, not with a group or any other student!


1.1 Deliverable


You must turn in a PDF copy of your nal exam. There is no minimum or limit to how much you can write or how long your exam must be. I recommend draw.io (saving directly to your onedrive account) for all diagrams.


0 Questions


2.1 Question 1


Explain the pro's and con's of packet switched networks vs circuit switched, in detail. Find a P2P protocol in the application layer and its speci cation, provide a diagram of the message packet and explain each eld. Finally, please talk about how packet switched networks can be utilized to enforce net neutrality laws.


2.2 Question 2


Compare and contrast TCP and UDP, be as thorough as possible. In what situation would you use one over the other, give speci c situations and explain the pro's and con's. Explain how TCP Tahoe handles congestion control. Tell me what TCP BBR and how it works. Look at the TCP BBR code and be amazed at how many comments and e cent algorithms there are!!!! You will need to cite sources for this question especially.



2.3 Question 3


Explain how routing is performed at the network layer. Explain the following routing algorithms (you can use pseudo-code or English): Dijkstra


Bellman-Ford


0 You will need to look up and understand Bellman-Ford. It is similar to what we did in class.


2.3 Question 4


Implement a method that does Dijkstra's algorithm in the following graph class. The weighted edge graph class can be found at this link: Graph Class


. You will need to read the code, understand what it does and then modify it by adding a method that does Dijkstra's algorithm on the following graph. You will have to print the table or a string representation of the shortest path for me to see in class. **Please do not put this on your Github until you have handed in the nal**


HINT: You need to make a table, update that table as you pass it through each node and its nodes connections. You can do this easily with recursion.


2.5 Question 5


Explain how routing works at the Link layer. Explain how a switch works. Why should we use a \star" topography rather than a bus topography or a ring topography for a network.


2.6 Question 6


Explain Cyclic Redundancy Checks. Give an example (not one from class) of a complete CRC check. I want you to talk about the generator function also (something I did not cover in my lecture). Cite your sources on this question especially.


2.7 Bonus


Email all the members of the FCC commission requesting them to vote your way on net neutrality before the nal and attach those emails onto this for 1 point each. If you don't know what net neutrality is please look into it and watch the video at these links: Net Neutrality I and Net Neutrality II.


Emails for all members of the fcc: Ajit Pai, Chairman : [email protected]


Mignon Clyburn, Commissioner : [email protected]


Michael O'Rielly, Commissioner : Mike.O'[email protected]


Brendan Carr, Commissioner : [email protected]


Jessica Rosenworcel, Commissioner : [email protected]