Bandwidth Isn’t Enough

If a Web page takes five seconds to load at 1 megabit per second, how long does it take to load at 5 megabits per second? Obviously, the answer is one second. How about at 35 megabits per second? Obviously, the answer would be 1/7 of a second.

Unfortunately, the obvious answers are not the correct ones. Exhibit 18.3 from the Federal Communications Commission shows download times for a Web page based on the advertised bandwidth of several vendors.

EXHIBIT 18.3 Web Page Loading Time by Advertised Bandwidth

Source: Federal Communications Commission, Office of Engineering and Technology and Consumer and Government Affairs Bureau, “Measuring Broadband America: A Report on Consumer Wireline Broadband Performance in the U.S.,” 2011. www.fcc.gov/measuring-broadbandamerica.

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In other words, even at infinite bandwidth, a Web page still may not load all that much faster than at a megabit per second of bandwidth, due to the effect of latency. To put it another way, even if there were an infinite number of lanes on Route 80 (bandwidth), it still is going to take a few days to drive from the East Coast to the West Coast due to the speed limit and distance (data rate, speed of propagation, latency).

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