An ISP Tortoise and Hare story

Donovan Colbert explains why a bandwidth cap really takes the fun out of the thought of a super-fast fiber connection to your home.

For awhile now wireless telcos have been flirting with usage caps and tiered data access plans, and recently Verizon did away with the "all you can eat" unlimited plans (which never really were "unlimited" in the sense that a reasonable person would expect, in most cases). A relative uproar of online indignation was the result. More recently, Netflix announced a new pricing structure that increases costs for both DVD delivery and content streaming.

There are different opinions on what this means and why it is happening. Many have suggested that it is a response to the major studios having more distribution options as viable competitors to Netflix arrive on the market; however, a common thread seems to be that an incredible increase in the amount of devices consuming very rich content across the Internet is causing a bottleneck that threatens to choke the Internet. This ZDNet post by Steven J. Vaughan-Nichols proposes exactly this case.

There is probably a lot of truth to both ideas. I have no doubt that the media studios are shopping around the various streaming content providers, as well as considering providing their own libraries directly, and that puts a burden on Netflix to offer more for digital streaming rights to remain competitive. Devices like the iPad and many recent Blu-ray players have made it more affordable and easier to stream Netflix to a PC in your office, as well as to the large-screen TV in your living room. Because of this, more families are consuming an unprecedented amount of Internet bandwidth on a regular basis. I've recently seen Blu-ray DVD players under $100 that offered Netflix streaming as a feature.

But in all this analysis, it seems like everyone is missing a deep and unfortunate truth in this discussion. In a very real sense, bandwidth caps not only affect your ability to stream and to consume other content by putting a meter on both, but they also make your "speed tier" a marketing ploy that has a lot less meaning in real life. In effect, a bandwidth cap is also a speed cap. What good is a 20mb fiber connection to your door if you can consume all 250 GB of bandwidth available in less than a week at that speed? It would be like having a car that has a theoretical top speed of 500 miles per hour, but will never have enough road to be able to achieve that top speed.

This isn't something that is isolated solely to technology, although technology has seen more than its fair share of scandals surrounding technical specs that have little or no relevance in reality. For instance, in the world of pickup trucks and towing ratings, frequently the maximum towing weight that a manufacturer specifies has little real world meaning for a number of reasons. I won't go into a lot of detail about this, but if you're rated to tow 9,500 pounds but your wheelbase is short, you're only safe towing a very small trailer loaded with lead bricks, or a much longer trailer that is towing something relatively very light, such as a boat. Other factors, such as your maximum tongue weight, combined gross vehicle weight, or the fact that the tow rating assumes no passengers and no options, means that very few vehicles used to tow come anywhere near being capable of towing the weights that are advertised in commercials.

A similar scandal ignited years ago in technology when people realized that the 17" rating on a monitor was not only diagonal, not horizontal, but also measured the entire tube, much of which might be hidden under the plastic bezel. Many consumers were finding that their 17" monitor might have as little as 15" of viewable diagonal space. A round of class-action lawsuits resulted, and suddenly we saw advertisements that proclaimed, "17" Monitor, 15.25" viewable, measurements are diagonal." Many readers will say, "caveat emptor" (the burden is on the consumer to understand the details), but I think this is deceptive and dishonest marketing, and it is on the vendor or manufacturer to accurately represent their goods or services.

In this case, your ISP is selling you a "monthly" service, and that service is rated in an up/down speed. In the past, this was all you needed to know, because those were the only figures being calculated. We'll ignore for the moment that in many cases many vendors were incapable of delivering the "maximum possible throughput" advertised. But when you add a bandwidth cap on top of those other two figures, you change the entire equation. I'm not a mathematician -- in fact, math is probably my weakest subject -- but I can see there is an equation here and that a person who is smarter than me could plug those figures in and come up with a figure that indicates the real maximum speed you're getting, if you want to have your connection work the entire month as promised. With 24 hours in a day, 30 days in a month (for our equation), a maximum speed of X, and a bandwidth cap of Y, when you work the numbers out, that is the real maximum speed your ISP is delivering to you (I had an associate figure out the math for me):

1.5mb/sec x 60 sec x 60 mins x 24 hours x 30 days = 3,888,000 megabits max theoretical throughput per month.

That converts to 486,000 megabytes.

A 1.5mb line with no cap running 24x7 for a month could transfer ~475 Gigabytes of data in a month. This is approximately 59 full DVDs of data in a month.

If you add a cap, 1.5 over 475 GB is equal to X over 250 GB

475x = 375 and x = 375 over 475, which equals 0.78 mb/sec (megabits).

So with a 250 GB cap on a 1.5 GB line, your actual theoretical speed (if you wanted to use your line 24x7 over a 30 day subscription period) would need to be throttled to 0.78 mb/sec.


Ultimately, this is all theoretical, and most of us can see that for the typical user, it is unreasonable to expect that they'll be using their pipe at full speed for an entire month. The fact remains that adding a cap makes the maximum advertised speed even less applicable, though. Actually, the faster your service is rated at, if the cap remains the same, the quicker you can consume your maximum bandwidth capacity allotment for a month, finding yourself potentially sitting at home in a dark room, unable to stream Netflix or even check your Facebook account.

A bandwidth cap really takes the fun out of the thought of a super-fast fiber connection to your home. It is an ISP Tortoise and Hare story. Slow and steady will get you through the month, while a fast connection might leave you stranded and out of gas just a short distance from the starting line.

It's time to break out the board games and start working on your Rummy technique.