Cox Kicks Off Throttling Test
MSO Says Congestion-Management System Applies Only to Upstream Traffic
By Todd Spangler -- Multichannel News, 2/12/2009 8:27:40 PM
Cox Communications this week began a single-market test of a congestion-management system designed to temporarily delay "non-time-sensitive" applications -- but only in the upstream direction -- during times when the network is exceptionally busy.
Jay Rolls, Cox senior vice president of technology, said the MSO currently has no plans to throttle downstream traffic.
"We only really have to battle this on the upstream," he said in an interview. For downstream traffic, "it's my opinion that DOCSIS 3.0 will make that a non-issue as we bond downstream channels" and increase overall per-node bandwidth capacity.
The operator is conducting the test in its Kansas-Arkansas system, which serves 447,800 basic video subs. (The company does not disclose broadband subscribers by market.) Rolls declined to identify the vendor Cox is using in the test.
The system, Rolls emphasized, takes action only when upstream capacity becomes constrained. Asked how frequently the network gets clogged, he would say only that it's an "unusual" occurrence.
"One of the things we hope to get out of the test is put a typical number to that, but [a congested network is] more unusual than the norm," he said.
The automated system works like a traffic signal that regulates the pace of cars as they merge onto a highway, Rolls said. When the network is at or near full utilization, time-sensitive Internet traffic like Web pages, voice calls, streaming video and online gaming will have priority over less time-sensitive traffic, such as file uploads and peer-to-peer file sharing.
Rolls said the test will probably take four to six weeks to return initial results, assuming the proper data is being collected from the equipment. "We may get into this and find out we may not be able to measure this properly," he said.
When Cox disclosed the bandwidth-throttling plans last month, it was immediately criticized by public-interest group Free Press, which said it was "concerned about any cable or phone company picking winners and losers online."
The question posed by Free Press and others, including peer-to-peer video distributor Vuze: What gives Cox the right to decide what is "time sensitive" and what isn't? The MSO is claiming it intends to work collaboratively with customers, interest groups, regulators and others to arrive at the answer.
"We gave it our best shot out of the chute to get the buckets right," Rolls said. "I imagine we may make some adjustments. If it's a time-sensitive application, then we want to be leaving that alone.... We don't want to have someone have their service visibly degraded."
The cable industry's network-management practices became a political flashpoint last year, after activists and customers called Comcast to task for cutting back bandwidth to peer-to-peer applications like BitTorrent.
Comcast's P2P targeting became the subject of a Federal Communications Commission investigation, and the agency eventually issued an order barring Comcast from employing that technique. The cable company has since moved to a "protocol agnostic" bandwidth-management approach that limits the heaviest bandwidth users.
Cox opted to forego a user-centric bandwidth-management approach because it believes prioritizing time-sensitive apps -- like voice over IP -- will yield a better experience for all users, according to Rolls.
He said Cox's trial does not single out particular services but rather attempts to group together "classes of applications." The alternative to implementing some kind of congestion-management system, he added, "is that everything has problems."
Asked whether adding more upstream capacity would address the issue, Rolls said Cox is already expanding the capacity of its hybrid fiber-coaxial plant, aiming to upgrade 80% to 1 GHz by the end of 2010.
Upstream congestion management "is a tactical tool, not a strategic tool," he said. "It's not a substitution for investing in the network -- it's not a capex-avoidance exercise."
The Cox Business network, which provides service to commercial customers, is not subject to the bandwidth-throttling test, Cox director of media relations David Grabert said: "We manage that network a different way."
As for the suggestion that the cable company is seeking to inhibit peer-to-peer applications to block a competitive threat on the video front, Grabert claimed that the new system will actually encourage Internet video use by allowing Cox to "deliver a better experience for customers."
Privately held Cox, the third-biggest U.S. cable operator, has more than 4 million residential broadband users nationwide.
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