Cisco Chips In For ‘Full Duplex’ DOCSIS

Taking aim at cable’s symmetrical, multi-gigabit future, Cisco Systems has introduced a silicon reference design for “Full Duplex” DOCSIS, a project underway at CableLabs that could continue to forestall the need for MSOs to squeeze more life out of their HFC networks and forestall the need to pull fiber all the way to the home. 

Cisco said it’s contributing the design on a royalty-free basis to the cable industry in order to accelerate the technology’s development and eventual deployment.

CableLabs introduced the concept of Full Duplex in February, declaring then that the project was in the feasibly/innovation phase and that the hope was that it would eventually become an enhancement/addition to the DOCSIS specs. DOCSIS 3.1 is currently designed to support downstream capacities of 10 Gbps down and at least 1 Gbps upstream. Full Duplex aims to get rid of those upstream/downstream spectrum splits and pave a path to symmetrical 10 Gbps capabilities.  

Full Duplex DOCSIS is being optimized for “passive” HFC networks as MSOs push fiber deeper and continue to eliminate the amplifiers present between the node and the home. Up for debate, is whether it makes more sense to take that route or just take fiber the rest of the way. DOCSIS gear vendors like the notion of Full Duplex in part because it helps to preserve their technologies and provide a path to future product upgrades.

Though Full Duplex is considered a longer-term project for the cable industry, which is just now starting to deploy D3.1, Nokia demoed a prototype of the concept, something it called “XG-CABLE,” in May at the INTX show in Boston.

CableLabs has said that Full Duplex will require some key tech around self-interference cancellation.

Cisco said more than 20 of its engineers developed a “validated” reference design for a “digital echo canceler” that can maximize HFC capacity,  and have defined a “multi-slice scalable echo canceler (EC)” for the emerging Full Duplex DOCSIS specs that can work with cable modem termination system (CMTS) architecture.

The technology is  also scalable for a return path from 200 MHz (1.7 Gbps) to 1.2 GHz (10 Gbps), said Cisco, which is demonstrating it at this week’s CableLabs Summer Conference in Keystone, Colo.

“By making this royalty-free design available to the industry, we can help our cable customers evolve to more rapidly deploy virtualized, fiber-deep, and all-IP infrastructures,” John Chapman, fellow and CTO of Cisco’s Cable Access Business, said in a statement.“We hope to accelerate the transformation of the cable industry to deliver multi-gigabit speeds and new high bandwidth services and products, and in the near future, customers can begin to enjoy the benefits of Full Duplex DOCSIS technology.”

Cisco’s contribution also earned some praise from the MSO community.

“DOCSIS 3.1 Full Duplex with up to 50 times more upstream capacity than today and echo cancellation technology, is further evidence that DOCSIS and the cable network itself has a long, useful life ahead,” said Jeff Finkelstein, executive director, Network Strategy, Cox Communications. “The work being done on Full Duplex by the MSO, vendor and CableLabs team shows that the cable network will continue to evolve and deliver high bandwidth services for many years, enabling our customers to enjoy the services most important to them to meet their future needs.”

“As we continue adding new DOCSIS 3.1-powered gigabit markets and customers across our footprint, we’re excited to see that the pace of innovation is still accelerating ahead,” added Dr. Robert Howald, vice president, Network Architectures, Comcast. “Full Duplex represents an important evolutionary step for DOCSIS 3.1, and we are actively participating with CableLabs and industry partners on this key initiative.”