Research shows data caps dont effectively target an ISPs most expensive customers

Rich Fiscus
8 Dec 2011 5:19

ISPs have been arguing for years that the heaviest data users should pay more for their service because they put a bigger strain on the network. This is the primary rationale for tiered data plans which cap downloads at varioius sizes and charge overage fees for additional data.
A new report from Benoît Felten challenges that assumption based on analysis of traffic data from an unnamed North American ISP. His conclusion based on that analysis is that heavy data users do not, in fact, put a disproportionately large strain on ISP networks.
While the study itself must be purchased if you want to read the details, he has posted a free summary of his key findings.

• The top 1% of data consumers (hereafter Very Heavy consumers) account for 20% of the overall consumption.

• Average data consumption over the period is 290 MB, while consumption for Very Heavy consumers is 9.6 GB. Thisroughly equates to data consumption of 8.7 GB and 288 GB per month, respectively.

• However, only half of these Very Heavy consumers are customers of the highest service tier (6 Mbps), which implies that half of them have bandwidth usage restricted to 3Mbps (the next service tier) or lower.

• 61% of Very Heavy data consumers download 95% of the time or more, but only 5% of those who download at least 95% of the time are Very Heavy data consumers.

• While 83% of Very Heavy data consumers are amongst the top 1% of bandwidth users during at least one five minute time window at peak hours, they only represent 14.3% of said Top 1% of users at those times.

So what does all that mean? The key points are the first and last. Despite the fact they consume 20% of the data flowing across the network, the heaviest data users account for less than 15% of the heaviest data consumers during peak times.
In other words many other users have just as great an affect on peak usage. This is important because peak usage is essentially how you can measure the bandwidth cost for the ISP. That cost remains the same even when no one is using the service. Unlimited downloading during non-peak hours doesn't cost the ISP anything extra.
Further down in his post he sums this up, writing:

The correlation between real-time bandwidth usage and data downloaded over time is weak and the net cast by data caps captures users that cannot possibly be responsible for congestion. Furthermore, many users who are "as guilty" as the ones who are over cap (again, if there is such a thing as a disruptive user) are not captured by that same net.