Saturday, April 4, 2009

Demystifying Bandwidth, or The Internet Is Not A Natural Resource

We need to get a couple things clear before this gets too out of hand.

  • Bandwidth is not the data you consume or produce.
  • Bandwidth is not a natural resource.

This seems to be of some confusion especially among Time Warner Cable executives. They continue to state incorrectly that some customers are "using up" more than their share of bandwidth. They also suggest that by sorting customers into tiers will alleviate the bandwidth problem because you'll pay for what you use.

Two Problems

There are two problems with that line of thinking and they go straight back to the two things I made clear at the top.
  1. Bandwidth is the amount of data that can be simultaneously transferred across a network path (such as from your house to Time Warner's central office to the Internet). This means that if Time Warner's total bandwidth for a single connection from my street to the Internet was 32 Mbps (that's megabits, not megabytes per second) and only two people on my street were using a full 15 Mbps connection at the same time, Time Warner would still have 2 Mbps of bandwidth available for others to use.

    To that end, those two people could continue on transferring data at 15 Mbps forever and the remaining 2 Mbps would still be available. Nothing's being consumed except the space in which to transfer data. When one or the other stops transferring data their 15 Mbps of bandwidth frees up and now 17 Mbps is available for others to use.

    The problem Time Warner is running into is that it oversold its available bandwidth and now that more and more people are actually using their full connections there isn't enough space (bandwidth) for everyone to transfer at their full speed at once. As you can see, just because you pay more for more data usage doesn't mean there's going to be space for you to transfer that data if enough people are in the same tier as you.

    I'll revisit this idea in a moment.

  2. When bandwidth is used it does not go away permanently. Unlike water, gas, or electricity -- all three of which must be produced or refined before (and sometimes after) consumption -- bandwidth does not require any pre- or post-processing before it's available to another user after being used.

    Bandwidth is replenished the instant someone stops using it. Think of it like a rubber band. This rubber band is special in that it cannot break, but it does have a limit to how far it can stretch. Now imagine pulling on that rubber band a little bit. How much it's pulled is analogous to how much bandwidth is being used. As more and more people try to pull it a little bit further it stretches to the point where it cannot stretch anymore. This is the "used up" point.

    As soon as one person lets go of their section of the rubber band it relaxes a little bit such that another person can pull on it. This is the elasticity of bandwidth -- it becomes available for another user immediately after it is released (not actively transmitting data). How does one meter elasticity? You're not losing or gaining anything, simply pulling and releasing. Bandwidth is not a natural resource and it does not get created or consumed in the same sense as a natural resource.
So now we understand that bandwidth provides us a means to transfer data, not a measure of the data we transfer (only the rate at which we do so). This means that a low bandwidth connection can transfer hundreds of gigabytes of data while still allowing many other people to do the same. Likewise, a high bandwidth connection will reduce the number of people who can simultaneously transfer data.

Time Warner Water Company

Question: If Time Warner Cable is concerned that the amount of bandwidth available will not meet demand at the access rates they sell (10 Mbps or 15 Mbps), they why aren't they building out their infrastructure to meet the demand?

Remember the first problem of oversold bandwidth? Let's revisit that...

Imagine Time Warner Cable ran the water utility (we'll call them Time Warner Water), then their story might be something like the following:

Time Warner Water (TWW) lays 12" water mains down each block of the city of Rochester in 1905 thinking pipes that size would be more than enough to meet water demand for the current residents. TWW charges each resident a flat monthly fee for unlimited water flow at a rate of 10 gallons per minute.

Most residents at the time did not use much water other than to run their tap and toilet and they were content. A very few residents used their water for gardening and cleaning, but they did not cause a problem for other residents because there was more than enough water pressure for everyone.

Over time houses are updated with appliances and additional bathrooms all of which use an increasing amount of water. Consequently, increased demand is placed on the common water main. Soon people start noticing low water pressure and poor rate of flow from their hoses when they're out watering their lawn in the evening at the same time as everyone else on the block.

Some residents complain to TWW and say they're not getting the flow promised for their monthly fee. TWW's solution to the perceived common problem is to roll out a tiered pricing structure whereby each resident will be charged a base rate for the amount of water they use plus additional charges if they go over that amount.

Some people don't see this as a big problem and fall under the low-use tier of consumers. Most of the rest of the block determine they are medium or high quantity users and pay for the middle- and high-end tiers.

One evening everyone on the block is out watering their lawn again and low water pressure again occurs even though they've all paid for their usage. In this scenario, we're assuming no one is going over their limit, they're simply all using the water at once.

Do you see how the tiers are not a solution to the problem?

Time Warner Cable's real solution

What hasn't been made very clear in Time Warner Cable's communications is that access speed will be determined by your tier as well. This means if you're in the bottom tier -- the less than 5 GB / month tier -- you will have a lower bandwidth (perhaps 2 - 5 Mbps). If you're in the top tiers -- the 40 GB or 100 GB / month tiers -- you will have the same bandwidth you're used to now (between 10 and 15 Mbps).

Oh ho! Now we start to see how Time Warner will try to make this work. They'll slow down the low-bandwidth users so they don't take up so much space in the "Internet tube" and give the high-bandwidth users more space to download data. The side effect of course is two-fold:
  1. People who infrequently use the Internet now but see pages load very quickly will find their pages load much more slowly even though their monthly billed rate may not have gone down (or may have gone down only slightly).
  2. People who frequently use the Internet will be able to download the same amount of data they do now but that amount probably far exceeds the 40 GB monthly cap leading to excessive overage charges.
In both cases Time Warner makes out like a bandit by degrading the speed of service for infrequent users and making it simple for frequent users to go over their cap and incur additional fees.

What Time Warner needs to do is stop overselling its bandwidth. If it can't service all of its customers at peak times at 15 Mbps, then it needs to lower the maximum speed to something it can handle at peak times or upgrade it's connection to the Internet backbone (make the water mains bigger).

Charging for data usage is simply ingenuous, inaccurate, and completely missing the point of bandwidth. What they're really doing is finding a way to charge you more for less, and I'd let them know what you think about that.

And by the way, this goes for Comcast, AT&T, Rodgers, Sprint, T-mobile and any other ISP or cell phone carrier charging for data transferred instead of access speed.

No comments:

Post a Comment