Cable for broadband speed, telcos for consistency in service and advertising

by Steve Blum • , , , ,

More likely so.

DSL is better at delivering advertised download speeds than cable, but cable modem service is still faster. That’s one of the conclusions reached by researchers for the U.S. National Institute of Standards and Technology after sifting through broadband test data collected by the FCC in 2011.

DSL broadband provided connections on average delivering download speeds above 80% of the assigned speed tier more than 80% of the time. By contrast, a significant fraction of cable connections received less than 80% of their assigned speed tier more than 20% of the time. One must keep in mind that cable connections typically have higher download speed tiers than DSL connections…the average download speed tier for DSL connections was 5.4 Mbps vs. 13.5 Mbps for cable connections.

In California at least, phone companies tend to be more granular in the broadband availability data they provide to regulators than cable companies. Typically, data for any given city will show a range of advertised DSL speeds across different neighborhoods, while cable companies generally claim to be able to deliver their top tier of service everywhere.

Estimating the actual speeds delivered to customers requires applying a discount to those claims. The NIST data suggests that it is appropriate to apply a steeper discount to cable claims, as I have done in several analyses of the California data. Even so, the resulting estimates still tend to give cable the edge, which is also in line with the NIST findings.

DSL customers are more likely to get the service they think they’re paying for, but with faster speeds, cable customers might not notice the difference.