Cable operators -- led by Charter Communications -- clearly delivered superior performance for Netflix movie streaming compared with telcos over the last three and a half months, according to the video-rental company's ranking of 16 U.S. Internet service providers released Thursday.
Netflix, which surged past 20 million subscribers to close out 2010, plans to publish the rankings monthly to shine a spotlight on which ISPs are capable of handling its HD streams -- and which are lagging.
The company may have an ulterior motive in publishing the rankings. Netflix wants to ensure that neither it or its content delivery network providers are required to pay additional fees to the last-mile ISPs in order to accommodate the significant influx of traffic its service represents, and could be looking to use the performance ratings as a way to compel providers to increase network capacity to match their peers.
Currently interconnection fees are the central issue in the standoff between Comcast and Level 3 Communications, one of Netflix's primary CDNs.
"We think the cost sharing between Internet video suppliers and ISPs should be that we have to haul the bits to the various regional front-doors that the ISPs operate, and that they then carry the bits the last mile to the consumer who has requested them, with each side paying its own costs," Netflix CEO Reed Hastings, along with CFO David Wells, wrote in a Jan. 26 letter to shareholders.
On Netflix's ranking, Charter topped the list among American ISPs, with 2.67 Megabits per second average over the period from Oct. 1, 2010, to Jan. 15, 2011.
Others in the top tier, with greater than 2.2 Mbps of throughput, were all cable companies: Comcast, Time Warner Cable, Cox Communications, Cablevision Systems, Suddenlink Communications and Cable One.
Verizon Communications was in the middle of the pack, at roughly between 2.0 and 2.2 Mbps average throughput, followed by AT&T, Windstream Communications, BellSouth (now part of AT&T), Embarq (now part of CenturyTel) and Qwest Communications.
The bottom three performers were Clearwire, CenturyTel and Frontier Communications.
In Canada, the story was the same: Cable operator Rogers Communications led with a 3.02 Mbps average, followed by Shaw Communications. The country's two major telcos, Bell Canada and Telus, delivered lower average throughput, Netflix found.
Netflix uses several content distribution networks, including Level 3, and customers' PCs or devices can adapt to changing network conditions by selecting the network path that's currently giving them the best throughput, director of content delivery Ken Florance wrote in a blog post Thursday.
"Netflix streaming performance ends up being an interesting way to measure sustained throughput available from a given ISP over time, and therefore the quality of Netflix streaming that ISP is providing to our subscribers," he said.
Florance explained that Netflix was trying to "highlight what's achievable in terms of HD performance on the various ISP networks" by analyzing data collected from hundreds of millions of long-duration high-definition video streams.
The Netflix charts show a time-weighted bit-rate metric to represent the effective data throughput subscribers receive over each ISP.
Netflix currently provides HD streams at a maximum of about 4.8 Mbps, although with the adaptive bit-rate streaming no client would sustain that throughput from start to finish, Florance said. However, he added, "the higher the sustained average, the greater the throughput the client can achieve, and the greater the image quality over the duration of the play."