Comcast's decision to put a 250-gigabyte cap on monthly bandwidth use for its residential customers may look like a generous number, but some critics suggested the cap may cause problems for users in the future.
Comcast announced late Thursday that starting Oct. 1 it will have a 250G-byte cap on monthly residential bandwidth, with the broadband provider saying it may send warnings to subscribers who go over the limit. If a subscriber goes over the limit a second time within a six-month period after getting a warning, Comcast will suspend the customer's account for a year.
Less than 1 percent of Comcast users will be affected by the limit, and customers who go over the 250G-byte cap will not automatically be warned, depending on whether they are in that top 1 percent, said Charlie Douglas, Comcast's director of communications. In the past, Comcast did warn high-bandwidth users and cut them off after a second warning, but the company did not have a firm bandwidth cap.
The announcement leaves many questions unanswered, said Art Brodsky, communications director for Public Knowledge, a digital rights group that's been critical of other Comcast network management efforts.
"At the moment, it seems relatively benign, but there are dangers lurking," Brodsky said. "Will Comcast count some traffic against the cap, but not other traffic -- as in Comcast-generated video?"
It's unclear whether Comcast traffic, including its VoIP (voice over Internet protocol) service, would be counted in the cap. Douglas didn't immediately return a phone call seeking a clarification on that issue.
But in an earlier interview, Douglas defended the cap, saying most Comcast customers use less than 3G bytes of bandwidth a month. "We think 250 [GB] is an extremely large amount of bandwidth," he said.
Other broadband providers have looked at bandwidth caps as well, with some considering caps as low as 5G bytes per month. At least two other providers in the U.S. and Canada have instituted caps, Douglas said.
The bandwidth cap doesn't appear to help with network congestion, Brodsky added. "A low-bandwidth user downloading an HD movie at 8 p.m. in peak time puts more stress on the network than someone who downloads lots more in the middle of the night," he said. "If fewer than 1 percent would be affected by this, what's the point?"
Brodsky and Om Malik, founder and senior writer at the GigaOm technology blog, also questioned how Comcast customers will know if they're getting close to the limit. Comcast has advised customers to search online for bandwidth monitoring tools if they want to know how close they are to the limit.
"If they are going to put caps, then they need to give us what I think is an acceptable expectation: a meter," Malik wrote Thursday. "Figure out a way to tell us what is our monthly usage, and let us know if we are running up against a 250 GB cap, we know when to stop ..."
Malik also questioned Comcast's estimates about how many e-mails a subscriber would have to send, songs they'd have to download, or movies they'd have to download to reach the cap. On one Comcast Web page explaining the caps, the company gives two different sets of numbers, Malik pointed out. On one part of the page, Comcast says a user would have to send 40 million e-mails or download 50,000 songs to reach the cap, and further down the numbers change to 50 million e-mails and 62,500 songs.
The 50 million e-mails is based on an estimate of 0.5 kilobytes per e-mail. "If you believe the 0.05 kb/e-mail then you also believe in the Tooth Fairy," Malik wrote.
Some critics raised concerns that the 250G-byte limit may be generous at the moment, but broadband users' bandwidth needs will continue to increase.
Earlier this month, the U.S. Federal Communications Commission struck down Comcast's past network management practice of slowing BitTorrent peer-to-peer traffic in an effort to reduce congestion. The FCC ruled that Comcast was violating so-called net neutrality principles by targeting a certain kind of Internet traffic.
"It remains unclear how the cap announced today helps solve Comcast's supposed congestion problems," said S. Derek Turner, research director of Free Press, another digital rights group critical of Comcast's past network management. "Though the proposed cap is relatively high, it will increasingly ensnare more users as technology continues its natural progression."
Turner applauded Comcast for being open about its caps. Well-disclosed caps are a better short-term solution than "Comcast's current practice of illegally blocking Internet traffic," he said.
Comcast will review the broadband caps periodically and look at whether they need to be increased, Douglas said.
Some Internet posters also questioned if the bandwidth caps violate customer agreements offering unlimited service. Comcast in past years has advertised that subscribers have unlimited downloads.
But Comcast doesn't have contracts with most customers that promise unlimited bandwidth, Douglas said. Comcast's terms of service allow the provider to change those terms, and generally focus on acceptable use, he said.