In today's Tech Life column about broadband data caps, I told the story of Andre Vrignaud, a Seattle gaming consultant who says he was suspended for a year by Comcast because he twice surpassed the company's 250-gigabyte-per-month "excessive use" cap.

Comcast, which imposed the cap in 2009, is hardly alone. Five of the seven largest broadband providers now impose some sort of cap, and a sixth, Time Warner Cable, is experimenting with one. Only Verizon has refrained so far - and, as I reported, it's not making any hard promises.

That's a shame, because Verizon could be singing its technological advantages from the rooftops. "We don't see the congestion that the cable companies are seeing," John Schommer, Verizon's director of broadband security and cloud services, told me. "We have a network that can handle a substantially higher volume of traffic." And Schommer can rattle off the tech specs to back that up: a network that can deliver 2.4 gigabits downstream shared among 32 customers, versus a good cable system's 320 megabits per second that he says may be shared, in a good case, among 200 customers.

But perhaps more significant, Verizon has seen no necessity so far to cap its DSL customers, either. Which brings me back to Comcast and its cap-happy brethren, CenturyLink, Charter Communications, and Cox, all of which threaten to cut customers off for blowing through a cap that at Charter can be as low as 100 gigabytes per month and at Cox as low as 30 gigabytes.

Bandwidth is increasingly cheap, as Netflix general counsel David Hyman argued last year in a Wall Street Journal op-ed titled Why Bandwidth Pricing Is Anti-Competitive.  But even if it weren't as cheap as it is, or if network upgrades required additional revenue to justify, the facts raise a basic question: Why aren't the other carriers doing what AT&T does - simply charging the so-called "data hogs" more for excess use?

Vrignaud, who would bristle at that term, has done extensive research on this question and has made a lot of noise in the technology trade press. His conclusion is that the answer is obvious: The real goal of the caps is to protect a business model that includes selling data-heavy content and services to customers over what the broadband companies consider their own "non-public" portion of the Internet, and to guard against competitive encroachments.  That's the same goal, by the way, that broadband providers have aimed for in their fight against net neutrality. Meanwhile, caps seem to have emerged as another way to skin the same cat.

Of course, Comcast isn't arguing that it wants to protect its turf - it's arguing the necessities of "network management."   And that's the argument Vrignaud is countering.

In particular, Vrignaud takes issue with the explanations Comcast has given repeatedly that monthly caps help spare other customers on a shared neighborhood node from congestion - a goal that he says could be addressed without a hard cap and even without overage charges.  He challenged the statements of Comcast's Charlie Douglas, who told me that Comcast believes it has set "a reasonable, transparent, and fair threshold" for excessive use, and that the number of suspended customers is "extraordinarily small."

"We feel that that is an extraordinarily large amount of data. That limit is there to make sure we provide a great online experience for every single paying customer," Douglas told me.

In an email exchange today with Douglas, copied to journalists and others, Vrignaud said Comcast continues to beg key issues - especially the questionable relationship between temporary congestion, which Comcast addresses through other network-management protocols, and overall monthly data usage.

The exchange began when Vrignaud asked a question he says Comcast has continually sidestepped:  "Why do you insist on completely cutting off data instead of using other more consumer-friendly options such as charging for overages or slowing internet use?"  It homes in on some of the key issues.

For instance, Douglas responded, in part:

... at Comcast, we don't currently offer a usage-based billing option. Instead, we have decided to take the approach of having a very generous and large threshold and policy that, ultimately, does not impact more than 99% of our customers. That's because in our experience, the overwhelming majority of customers who go over the threshold and who we call and ask them to moderate usage do so voluntarily.

We've worked hard to make our residential data usage threshold clearly known in our terms of service and on a webpage with numerous Q&As.

Last year, Andre, you made some thoughtful suggestions regarding how we could sharpen some of that language in those Q&As and we listened to you and incorporated that feedback. So, thanks again for that.

To which Vrignaud replied, in part:

... The question is not whether or not you "offer a usage-based billing option." The question is: Why do you insist on completely cutting off data instead of using other more consumer-friendly options.

And the question goes on to highlight several examples of more customer-friendly options, including: potentially charging for overages (as do your competitors), slowing internet use through careful throttling, or allowing people to use your network at night when it is presumably not under heavy load, and/or "congesting" neighbors.

Speaking frankly, I believe the the reason Comcast refuses to answer the specific question above (including discussing the consumer-friendly options) is that there is no good answer. There is no reason Comcast can't invest in simple APIs that would allow Amazon and Carbonite to enable their users to upload content at night when your network is under-utilized and hence has no "neighbor impact." And there is little to no correlation between heavy users and network congestion. ...

If you want to read more about the issues Vrignaud has so doggedly raised, you can find links at his website, where he's consolidated many of them into a single post: The Day Comcast's Data Cap Policy Killed My Internet for 1 Year.

With the expansion of Internet video and other data-heavy services, this issue will only grow in importance.  Caps may not matter to you today - Douglas says the median Comcast  customer uses just 8 to 10 gigabytes per month - but still matter to you next year, or the year after.

Netflix says HD video, for instance, can involve transmission of 2.3 gigabytes per hour, which means that by watching 25 hours per week you'd be closing in on the cap. I'm not at risk, but that's supposedly well below the average amount of TV watching in U.S. households today, and the Internet allows different family members to watch different things on different devices.

And that doesn't take into account the other cloud-based services, such as Carbonite's data backup or Amazon's media player, that tripped up Vrignaud and are just beginning to make their marks.

Or the next new new thing - which really may be what this debate is all about.

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