Homework 3 - P2P DHT Reaction

(1) Read the Looking Up Data in P2P Systems article by Hari Balakrishnan, M. Frans Kaashoek, David Karger, Robert Morris, and Ian Stoica.

As you read, try to think of situations where P2P systems like they describe might be used today. Actual specific programs or systems you yourself may have used or seen, or situations you can imagine where such a system could be beneficial, or places where you suspect the really are being used today. Or, alternatively, if you think P2P systems like these are not being used much today at all, why did they fail to catch on or fail to survive?

If you encounter terms you are not familiar with, try to look them up. You need to know what P2P stands for, and how it is different from the kinds of client-server protocols we have been studying. You need to know what a a hash table is (also called a "dictionary" or "map" or "hash-map" data structure). And you need to know what a hash function is... for the purposes of this paper: it's a mathematical function that takes as input any string, like a filename or a keyword phrase, or any aribtrary block of data such as a picture or text file, and generates a fixed-size "fingerprint" for that input, where the resulting fingerprint will be essentially just a random-seeming N-digit number that depends purely on the input data.

(2) Write a short reaction describing:

1. A summary, in your own words, of how these P2P systems compare to systems we have studied (like HTTP, POP, or DNS). Focus on the most important differences and similarities, both from a technical perspective (how the systems are implemented) and a user perspectve (how the systems are used or what they are intended to achieve).
2. One or two ideas in the paper you thought were most interesting, insightful, or novel, and why you thought so;
3. and one or two points you think could be a significant obstacle to the use of such systems today, and why you think so. For example, perhaps there are assumptions or arguments in the paper you think are simply wrong, misguided, outdated, or lacking.

(3) We may discuss this paper in class following the due date, so be prepared to ask questions and discuss.

Context is important: This paper was written in 2003: The internet was booming, with many households going online, Napster having boomed then collapsed just as quickly, new sharing protocols popping up, and "web" companies like Google and HotMail starting and growing quickly. Apple Music was more than a decade into the future. Netflix existed only as a DVD-by-postal-mail business. Blogs were a new thing. The "slashdot effect" was new and awesome (in both senses). On the other hand, the new Internet economy was poorly understood, the "dot-com bubble" was just starting to burst, Wikipedia, Facebook, MySpace, and YouTube were still a few years away. And though early network threats like the Morris Worm were 15 years old by this point, the world was now starting to see new, extremely fast and massive-scale cyber crime and denial of service attacks like the Code Red Worm. "Social Media" didn't exist, and instead there was optimisim that the internet would soon connect individuals across the country and the world to share ideas and data, fight censorship and authoritarianism, wipe away old structures and create amazing new things.

Be concise: Your reaction should be about a page of single-spaced text, but avoid all filler text and fluff. Just get to the point.

Know your audience: You should consider your reaction as a presentation to your classmates, all of whom (should) understand HTTP, POP, and DNS, and all of whom (should) have read the paper already. There is no need to rephrase or summarize all the ideas in the paper. Avoid filler text.

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