CPE 401/601 Computer Communication Networks

Spring 2012

Lab 3: Content Distribution

Due on Monday, Mar 12 at 1:00 pm

Complete the content distribution lab posted on WebCampus and (when applicable) insert snapshots of your configuration to answer in-lab questions.

Post-lab Questions

  1. Does it make sense for a single ISP to function as a CDN? If so, how would that work? If not, what is wrong with the idea?
  2. How would one design a CDN redirection mechanism using only HTTP 302 redirects or only DNS? What are the limitations of each approach? Is a combination of the two mechanisms feasible?
  3. Consider a 50,000-customer video server, where each customer watches three movies per month. Two thirds of the movies are served at 9 p.m. How many movies does the server have to transmit at once during this time period? If each movies requires 6 Mbps, how many OC-12 connections does the server need to the network?
  4. Suppose the Zipf's law holds for each access to a 10,000-movie server. If the server holds the most popular 1,000 movies in memory and the remaining 9,000 on disk, give an expression for the fraction of all references that will be to memory.
  5. Consider the following simplified BitTorrent scenario. There is a swarm of 2^n peers and, during the time in question, no peers join or leave the swarm. It takes a peer 1 unit of time to upload or download a piece, during which time it can only do one or the other. Initially, one peer has the whole file and the others have nothing. If the swarm's target file consists of only 1 piece, what is the minimum time necessary for all the peers to obtain the file? Ignore all but upload/download time.

What to turn in A soft-copy of your results and answers to the questions to be uploaded to WebCampus.