No. 1 operator looking to increase upstream capacity and reduce latency as DOCSIS 3.1 deployment reaches completion

ATLANTA - As it crosses the finish line on an 18-month mission to deploy DOCSIS 3.1-enabled services across its entire footprint, Comcast is already testing a new network configuration mixing Distributed Access Architecture with Full Duplex DOCSIS capabilities.

According to Robert Howald, VP of network architecture for Comcast, DAA is a "prerequisite to Full Duplex,” with the operator looking to deploy Full Duplex-capable, Remote PHY nodes.

“We see DAA as part of the train of evolution. We’re not going to wait years for Full Duplex to start deploying DAA” said Howald, VP, speaking at a pre-SCTE Cable-Tec Expo event Monday focused on DAA and featuring engineer representatives from a host of major operators, vendors and standards bodies.

Complete Coverage: Cable-Tec Expo 2018

While compound annual growth rates (CAGR) for demand of downstream bandwidth is decreasing, the CAGR is increasing for upstream broadband, up to about 25% - 30% from a longtime plane of around 20%. This can be credited to the proliferation of devices like surveillance cameras, but also the emergence of applications like virtual reality and advanced gaming.

“We want to go symmetrical,” Howland said, noting the 10 Gbps speed potential, in both downstream and upstream, for Full Duplex DOCSIS. “But we want to be in DAA to do that.”

DAA, he added, will “lead Comcast down the road to virtualization” of its network, allowing the operator to use “off-the-shelf” server components and delivering “tremendous scalability benefits for us at our head end.

Related: Comcast Reaches the Finish Line on DOCSIS 3.1 Deployment

“We prefer not to build new facilities if we don’t have to,” Howland added, echoing comments made minutes earlier by CableLabs’ Jon Schnoor on the potential of DAA to save on infrastructure real estate expansion, not to mention on cooling and power needs.

Howland offered up no specific time frame for deployment of DAA and Full Duplex (FDS) services. However, speaking shortly afterward, Steven Krapp, senior director of technology for vendor MaxLinear, said his company is working with Comcast on FDX trials, “seeing how the cable swinging in the wind effects the echo cancellation.”

With echo cancellation being core to a technology that involves the upstream and downstream frequency layers existing on top of one another, FDX requires that operators move to a node+0 environment. This isn’t as much of an issue for a company like Comcast, which has “pushing fiber deeper and deeper into its network,” according to Howland, almost reaching the point of the “optic nerve” of the subscriber.

But it is an issue to many operators, which don’t envision having a node+0 configuration in a 10-year time window.

According to Krapp, MaxLinear is working FDX amplifiers that will enable the technology to work beyond node+0. 

Related