CS 4873 Computer Networks, Class Problem 1


This is the problem I posed at the end of class on Thursday, August 28.
The first one to post a correct solution to the newsgroup utsa.cs.4873.s will get a very small amount of extra credit.


It takes me 10 minutes to drive to UTSA from my home, 4 minutes to get from the parking lot to my office, and 2 minutes to set up my notebook computer on the network. It takes 1 minute to shut it down and pack it up for travel. Once connected, I can transfer 500 K bytes per second. Home and work setups are identical.

Alternatively, I can use my ISDN connection from home. It takes about 10 seconds to type ftp hostname, login and get filename.
I can then transfer data at 10K bytes/second.

I am home on a Sunday afternoon and I must get a 20 Mbyte file from UTSA to home. Should I use the phone or drive? Suppose that the starting and ending situation has my notebook computer connected and set up at home.

  1. Which method should I use? Show how you got your answer.
  2. What amount of data is the trade-off point?
  3. What assumptions did you make to do this problem?
  4. What factors have not been considered?