DNS could slow broadband serviceBy Marguerite Reardon, CNET
News.com
August 17, 2006, 3:12 PM PT
A broadband provider's claim of superfast speeds may only be as
good as its weakest link, which could be its domain name server
software.
A report issued Thursday by Nominum, a company that sells domain
name system (DNS) server software, indicated that some broadband
service providers need to bulk up their DNS servers to ensure that
broadband users actually get all the benefits of their high-speed
connections.
"We hear stories about carriers spending billions of dollars to
build new fiber-to-the-home networks or 3G (third-generation)
wireless networks," said Paul Mockapetris, inventor of the DNS
architecture and chairman and chief scientist at Nominum. "But
broadband providers should also spend some money adding more DNS
capability. Pure bandwidth doesn't solve the problem if the DNS
servers can't respond quickly."
DNS functions as the "phonebook" of the Internet, mapping
text-based domain names such as www.cnet.com to the numerical
Internet Protocol addresses used by computers. Internet users
typically use the DNS service run by their service provider.
When DNS servers are running slow or when they drop queries, people
experience Web pages loading slower, delays in sending and
receiving e-mails, and poor response times when they're trying to
play interactive video games.
More than 48 million American households have broadband access
today, according to the Leichtman Research Group. To entice
consumers to use their service, phone companies and cable operators
have focused a lot of attention and marketing dollars on convincing
potential customers that their service is the fastest. Verizon
Communications is spending $20 billion over the next few years to
build a fiber-to-the-home network called Fios, which it claims
provides the fastest Internet access network in the United
States.
In the survey commissioned by Nominum and conducted by VeriTest in
April, Verizon's Fios network and its DSL (digital subscriber line)
service actually had the worst response times of any broadband
provider measured. According to VeriTest data, the Verizon Fios
service had an average DNS response time of about 180 milliseconds.
By contrast Comcast, which is a Nominum customer, had the fastest
response time of roughly 40 milliseconds.
Bobbi Henson, a Verizon spokeswoman, said the company has been
upgrading and tweaking its DNS servers over the past several
months. She also said the company has conducted its own tests with
VeriTest, which show very different results.
"We would dispute that we have the slowest DNS look-ups in the
industry," she said. "We conduct our own studies monthly. We are
always looking at the overall performance of our DNS servers and
tweaking them to improve performance."
At the end of the day, all the broadband providers in the report
had response times in either tens or hundreds of milliseconds,
hardly enough time for the average user to even notice, said Joe
Laszlo, an analyst at Jupiter Research. He acknowledged that
upgrading networks to increase raw bandwidth takes the bottleneck
out of one part of the network, and inevitably exposes flaws in
other parts of the network. But he said he doesn't believe DNS is
the biggest culprit in noticeably slowing Internet service.
"So much of the perceived performance of a service depends on how
fast your browser in your computer can process Web pages or how
quickly your graphics card can render images," he said. "Slow DNS
response times could impact the speed of the service, but I don't
think it's the No. 1, No. 2 or even No. 3 issue that creates
noticeable delays for users."