Comcast story in Ann Arbor News Jan 30, 2004 — numbers don’t make sense

Dear Ann Arbor News,

In the AP story about Comcast downloads that appeared in the business section of the Ann Arbor News on Jan 30, 2004, the story claims that some users are downloading a terabyte of data per month.

[The Ann Arbor News does not make available AP stories on-line so I have linked to an external source for this story.]

Most Comcast connections in the US are less then 1.5 megabits per second. Here in Ypsilanti Michigan, we get a faster connection. Comcast says the rate here in Ypsilanti is 3 Megabits per second, however this is speed is never realistically attained. But lets assume that a user could consistently get 3 megabits per second of bandwidth any where in the US. Three megabits per second is 986 gigabytes or 0.986 terabytes per month if you left your connection on and it was downloading full steam 24 hours a day for the entire month. That is no outages, no slow down, no running out of disk space, no computer crashes. Yet that number is less then 1 Terabyte and that assumes perfection on the connection. That never happens. Even here in Ypsilanti, there are slowdowns and outages every day on the Comcast network, that is the nature of the beast. And remember, the vast majority of Comcast users can’t get any thing faster then 1.5 megabits per second. So now you are talking less then half a terabyte per month.

For most Comcast subscribers, Comcast does cap upload and download rates. Yet the quote was that some users are consuming more then a terabyte per month. Unless Comcast doesn’t have any caps on download speed, there is just no way you can download a terabyte of data in a month on a 3 megabit per second or slower connection.

Someone should have questioned AP and Comcast on these facts.

And that 986 gigabytes is download bandwidth. Comcast severely limits upload speeds. Comcast claims in the article that people are running web servers and sharing music and that is consuming bandwidth. A web server for the most part only uploads data, not downloads. It is the upload or the delivery of the page to the requestor that consumes bandwidth.

Here again, somebody at the newspaper should have checked the math and how Comcast regulates their service.

In Ypsilanti the uploads speeds are a maximum of 256 kilobits per second. So if you setup a web server, which by the way is a violation of the Comcast terms of service agreement, but say you setup an illegal web server and you were uploading files flat out 24 hours a day, that would be 84 gigabytes of total bandwidth per month. Again that assumes perfection. But Comcast severely restricts upload. So it is impossible to consume a terabyte of data in a month because Comcast significantly limits the upload for any one customer.

It should also be noted that a large number of current Comcast subscribers across the country are limited to 128 kilobits per second of upload. So for them, the max upload in a month is 48 gigabytes.

Given this data, the numbers quoted in the article just don’t make sense. The anonymous Comcast employee said letters were triggered at 100 Gigabytes per month. Yet the most a Comcast subscriber could upload in a month is 84 gigabytes.

Even if you had a web server running 24-hours a day, you can never reach that limit so no one that is running a web server should ever trigger a letter.

Yes, it is true that you can add the upload and download speeds to get total bandwidth, but any computer geek will tell you that when you are uploading data on a cable modem circuit, you don’t get your max download speed. But assuming perfect conditions you just barely get a terabyte of data per month, at 1.07. But again, your theoretical maximum upload would be 84 gigabytes per month, there is no way you can exceed that limit if Comcast is limiting you to 256 kilobytes per second of upload bandwidth.

And all these numbers are theoretical based on the maximums that Comcast says is possible, not what is reality when it comes to uploads and downloads.

In Ypsilanti, the best download speeds are between 2.5 and 2.6 Megabits per second. Uploads run from 88 to 240 kilobits per second for most connections. Given real world numbers, the facts and figures quoted in your article just don’t make sense. As my daddy used to say, “that dog don’t hunt.”

In the article it also says that 30 minutes of high quality video can consume a gigabyte of data. Well how much bandwidth is that per second? It is 4.4 megabits per second. That is almost 1.5 times greater then the maximum speed mentioned in the article. So it isn’t possible to watch a high quality video in a real time video stream. There isn’t enough bandwidth.

It is definitely possible to exceed 100 gigabytes of total upload and download bandwidth in a month, but it is impossible to reach a terabyte and, if you are solely running a web server, it is almost impossible to exceed 100 megabytes in any one month.

Again why didn’t someone try confirm the facts you got from AP and Comcast?

Moreover, what is the actual source for the Britannica quote that the encyclopedia is 1 gigabyte worth of data? It is often quoted but how is that data derived?

So just how big is the encyclopedia? Well that depends, are you talking the CD-ROM version or the print? Are you talking words only or words and pictures? The article doesn’t say? So this number is rather pointless because there is no clarity on what you really mean. This is like saying the size of a volcano on Mars is twice the size of Delaware. That is nice info, it may even be true. But it isn’t very useful data, most people, including most reporters can’t tell you the size of Delaware. [Delaware is 1,954 sq mi]

According to the Encyclopedia Britannica, the printed version is 32 Volumes and 44 million words. Does that equal a gigabyte? There isn’t any way to tell. The story quotes an anonymous source at Comcast and apparently there was no verification with Encyclopedia Britannica or anyone else to confirm the numbers quoted about the size of an encyclopedia.

Then the story says that not having enough capacity could affect Comcast’s profit margin. How?

If you don’t have enough capacity then the network slows down but that doesn’t directly affect profits. I guess it could be argued that with not enough capacity to meet demand, subscriber counts would decrease. But I have checked news reports for the past year. I don’t see any stories about Comcast customers switching en masse to other providers because of capacity problems. In fact, Comcast has said their subscriber numbers are up and they have recorded record profits in the past year. That being the case, the conclusion that could be drawn is that Comcast has enough capacity to meet existing demand and since Comcast has been reporting record profits for the past year, high bandwidth users do not seem to be affecting Comcast profits. So this paragraph about Comcast profit margin doesn’t make sense given other facts in the story and other publicly accessible records.

It took me less then 10 minutes of fact checking to see that something is squirrelly with the numbers used in this article. Someone at the Ann Arbor News and AP could have and should have confirmed the data supplied by the anonymous source at Comcast before the article went to press. At a minimum someone at the newspaper should have confirmed the other numbers and facts quoted to make sure they made sense and were correct before going to press.


– Steve