docsis 3.1The cable industry took a step toward eliminating one of its oldest drawbacks with the completion of the Full Duplex DOCSIS 3.1 specification. The completed specification governs how data can flow symmetrically in both the upstream and downstream directions over HFC networks, enabling full duplex broadband.

“In the United States, more than 90 percent of households are connected to an HFC network, and consumers typically have higher download speeds than upload speeds,” Phil McKinney, president and chief executive officer of CableLabs, said in a press release. “By enabling Full Duplex DOCSIS, the upstream and downstream traffic can flow at up to 10 Gigabits concurrently, doubling the efficiency of spectrum use.”

This is a significant step for the industry. Cable networks initially were architected with far more bandwidth flowing downstream than upstream. This wasn’t a problem at the beginning of the broadband age, when upstream data flow was not significant.

Of course, that scenario has been turned on its head as consumers increasingly upload large data files, including photos and video. Home and small business customers now generate a tremendous amount of upstream data. Thus, DOCSIS 3.1’s symmetrical capabilities remove what would be a severe competitive disadvantage compared to fiber-based networks.

The full duplex version of DOCSIS 3.1 builds on the core DOCSIS 3.1 specification, which is in full swing for cable providers. Large-scale DOCSIS 3.1 deployments are underway for large and small cable MSOs alike.

The move to full duplex involves more than just minor tweaks to DOCSIS 3.1. CableLabs highlights some of what is involved, including passive HFC network characteristics, self-interference cancellation technology and intelligent scheduling.