1. Suppose a 1 GB file must be distributed. Assume there are 20 clients (or peers) in addition to the server, and that the following 20 numbers represent the download speed of the 20 clients, in Mb/s:

  • 2
  • 2
  • 3
  • 4
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 6
  • 6
  • 8
  • 9
  • 10
  • 15

Each client has an upload speed of one half its download speed.

The server has an upload speed of 50 Mb/s.

2. What is the minimum time, in seconds, that it takes to distribute the file in the client/server case?
3. Continuing with the previous question, what is the minimum number of seconds to distribute the file in the peer-to-peer case? Now, suppose we double the number of clients and the distribution of their speeds is unchanged, i.e., the file and server upload speeds are the same, the slowest download speed is unchanged, N is doubled to 40, and the sums of all the peer upload and download speeds is doubled. Now, what is the minimum time, in seconds, it takes to distribute the file in the client/server case?
4. Continuing with the previous question, what is the minimum number of seconds to distribute the file in the peer-to-peer case?



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