Casa Systems boasts ‘breakthrough’ in extended spectrum DOCSIS

Fixed and mobile vendor Casa Systems has upped its game on extended spectrum (ESD) DOCSIS 4.0, announcing last week its virtual converged cable access platform (CCAP) and Remote-PHY solution are interoperable with third-party DOCSIS 4.0 cable modems.

Casa Systems demonstrated the interoperability at a recent CableLabs event, claiming it was the “world’s first” to showcase full utilization of extended spectrum DOCSIS 4.0.

The extended spectrum variant allocates separate chunks of spectrum for the upstream and downstream lanes of traffic to reach 10 Gbps download speeds and 6 Gbps upload speeds.

Dell’Oro Group VP Jeff Heynen said Casa Systems’ demo “is the first combination of vCCAP plus Remote PHY Device to demonstrate full spectrum utilization” of extended spectrum up to 1.8 GHz in the downstream and 396 MHz in the upstream.

This means Casa Systems demonstrated 10-gig download speeds and 3 Gbps upload speeds, so the upstream capacity isn’t at the maximum 6-gig for DOCSIS 4.0.

Heynen explained while ESD can push upstream spectrum to 684 MHz, it’s likely most operators will either use 204 MHz – a high-split DOCSIS 3.1 configuration – or 396 MHz for the upstream spectrum.

“The move to 1.8 GHz will be mainly focused initially on pushing downstream speeds to 10Gbps to either match or exceed what fiber ISPs will be using as their billboard speeds,” he told Fierce. “So, operators will stick with the existing band split and then, over time, move to 300-396MHz in the upstream.”

Charter Communications and Cox are among the operators that are pursuing ESD for their network upgrades. Whereas Comcast is pursuing a full duplex (FDX) DOCSIS 4.0 approach, which involves the simultaneous transmission of data upstream and downstream using the same spectrum.

Heynen added, “It won’t be until much later that operators will move to 684 MHz.”

Despite Casa Systems touting a “breakthrough” in extended spectrum DOCSIS 4.0, the company reported declines in its cable business in the third quarter. Specifically, cable revenue of $17.5 million was down 42% year on year from $30.2 million.

On an earnings call earlier this month, Casa Systems CEO Michael Glickman said the shortfall in cable revenue “is not due to competitive market share losses but rather the delays associated with” operator network upgrades.

“As with most vendors serving this market, there has been a slowdown in spend during these transitions which have MSOs utilizing current capacity in their networks, as well as reducing inventory built through later stages of the pandemic timeframe,” he said.