C-DOCSIS: It’s Not Just for China

The first “C” in C-DOCSIS stands for “China,” but the budding, low-cost architecture tailored for high-density apartment buildings and other forms of multi-dwelling units could end up playing a significant role in a number of emerging cable markets around the globe, according to an analyst who tracks cable’s global broadband developments.

MSOs in southeast Asia and Eastern Europe are beginning to test the architecture or are making plans to do so, Infonetics analyst Jeff Heynen said.  

C-DOCSIS, he said, will work well in fiber-deep networks that rely on EPON or GPON to the MDU, then distribute services over coax via the in-building network, he said. “It could be an inexpensive way to get data services where you didn’t have them before," he said.

C-DOCSIS, after starting off as an off-shoot project sparked by Broadcom, has since been integrated into the CableLabs specifications, marking one of several decisions made recently as CableLabs folds in Cable Europe Labs and strives to become a global-focused R&D entity.

It appears that much of that initial work is complete. Versions of the Physical Layer Specification, Security Specification, and MAC and Upper Layer Protocols Interface Specification for DOCSIS 3.0 published earlier this month now reference C-DOCSIS annexes and other optional modifications.

As C-DOCSIS is crafted, only the network components are different than their traditional DOCSIS counterparts. Save for some minor modifications, C-DOCSIS uses traditional DOCSIS 2.0- and DOCSIS 3.0-certified cable modems. The C-DOCSIS Cable Media Converter (CMC) is akin to the cable modem termination system in today’s DOCSIS networks, but represents a lower-cost, stripped-down version that does not include the core routing features found in a regular CMTS. Outside of the C-DOCSIS sphere, Casa Systems is also targeting high-density MDU environments in China with a compact CMTS called the C1G.

China’s State Administration of Radio, Film and Television (SARFT) has already accepted C-DOCSIS as an access standard for the country’s next-generation broadband project aimed at sparking more competition for the nation’s telcos. With CableLabs now an official supporter of C-DOCSIS, the approach appears poised for other cable markets that rely on fiber deep architectures.

A C-DOCSIS vendor ecosystem is developing. China-based SumaVision's CC800-series product (pictured above) was the first C-DOCSIS product certified by the SARFT wired institute, according to a Broadcom announcement released in March 2013. Another Chinese vendor, ZTE, has also pitched in with an outdoor C-DOCSIS-based Ethernet-over-coax product called the ZXA10 EC9026.

Having C-DOCSIS join the official DOCSIS specs gives the budding platform more credibility while also “giving operators that looking at the technology a bit more confidence that it will be supported within the standards community,” Heynen said, acknowledging that C-DOCSIS deployment activity is currently small.

But Heynen said C-DOCSIS might also factor into a larger trend as the cable industry continues to noodle more distributed architectures that push capacity further toward the edge, rather than relying on massive, centralized hubs.

Some vendors are already pursuing the idea as the cable industry starts to develop strategies around DOCSIS 3.1, a spec in the works that will target downstream capacities of 10 Gbps and upstreams in the neighborhood of 2 Gbps.

For example, Gainspeed, a startup launched by Terayon Communication Systems co-founder Shlomo Rakib that was formerly known as Cohere Networks, is believed to be working on a “remote” or “micro” CMTS platform. Aurora Networks, meanwhile, has already developed a distributed QAM module that can be snapped into the vendor’s network nodes.

 “There are multiple approaches emerging for the distribution of the physical layer,” as MSOs mull next-gen access architectures and DOCSIS 3.1 strategies,  Heynen said. “There’s no clear indication as to which one will win out. Across the globe, operators are trying to figure that out.”