Question

Is Copper completely obsolete?

Here is a direct quote from “Why such slow Wi-Fi?” in a recent Los Angeles Times article:

“In an analysis of fixed broadband and mobile speeds in July, Speedtest ranked the United State No. 9 for broadband and No. 46 for mobile (Nos.1, respectively, Singapore and Norway. Last: Venezuela and Iraq). Part of the issue for Americans: Many of us still have home service based on copper wire, not fiber.
Craig Ganssle, chief executive of Camp3, which works on wireless infrastructures, explains this difference: Copper service is based on the speed of sound (generally about 1,125 feet per second if it’s 68 degrees and the air is dry), and fiber is based on the speed of light (about 984 million feet per second).”

With a few exceptions, most of us get our home Internet access through a cable modem and the wires that connect our modems to our ISPs are made of copper. Let’s assume you are streaming a Netflix movie. The nearest Open Connect appliance, which Netflix uses to host and deliver movies to customers (see Chapter 11, pg. 360), is 3 miles from your home. Let’s also assume you have already found the movie to watch and is ready to start. You click on the Play button, a one-bit signal is sent over the 3-mile copper wire to reach the Open Connect appliance, which then starts sending the digitized movie frames back to your home, also over the 3-mile copper wire.

Questions:
a. Given the quoted speeds above (i.e., 1,125 feet per second vs. 984 million feet per second), from the moment you click the Play button, to the moment the first frame of the movie appears on your screen, how long will it take (round-trip time) over a copper wire? Over a fiber optic cable?
Note: 1 mile = 5,280 feet
Round-trip time = (Distance / Speed) × 2

b. How does your calculated result over a copper wire compare to your own experience of streaming movies on the Internet, excluding any buffering time? Do you see any problem with what the expert in the article above was saying? Hint: this expert did not get some basic facts of physics right.

Answer 1