DOCSIS 4.0 interop hits record 9-Gig downstream speeds

CableLabs said its latest multivendor DOCSIS 4.0 interoperability test achieved a downstream speed record of 9 Gbit/s, an indicator that the latest wave of products is "nearing feature-complete status."

Light Reading has asked CableLabs what level of upstream speeds were achieved during the interop, which was held April 15-18 in Louisville, Colorado, and hosted by CableLabs and its Kyrio subsidiary.

Update: CableLabs said the interop saw upstream speeds of up to 2.4 Gbit/s.

The event focused on interoperability across DOCSIS 4.0-based modems and remote PHY equipment, including virtualized cores and remote PHY devices (RPDs).

In addition to setting a new D4.0 downstream speed record, the number of companies participating in the interop with modems and RPDs also set a record, Doug Jones, principal architect at CableLabs, explained in this blog post.

Casa Systems, CommScope and Harmonic supplied D4.0 cores. Within that group, Casa's cable assets could be going to Vecima Systems in the coming weeks, pending the outcome of a coming auction.

According to Jones, six suppliers – Calian, Casa, CommScope, DCT-Delta, Harmonic and Vecima – brought a mix of DOCSIS 3.1 and DOCSIS 4.0 RPDs. Five companies – Arcadyan, Askey, Hitron Technologies, MaxLinear, Sagemcom, Ubee Interactive and Vantiva – contributed D4.0 modems to the interop. Additionally, Rohde & Schwarz provided its DOCSIS 4.0 test and measurement system, while Microchip Technology participated with its clock and timing system.

Related:Broadcom's grip on DOCSIS 4.0 chips remains a concern

Mixing and matching

Testing scenarios included the use of a virtual core from one supplier, an RPD from another and D4.0 modems from multiple suppliers. "The products were mixed and matched to verify interoperability scenarios and speeds through the system," Jones explained.

A previous DOCSIS 4.0 interop held in February also focused on testing the full DOCSIS 4.0 ecosystem. Other D4.0 interoperability tests have focused on areas such as security and proactive network maintenance.

Jones said a big takeaway from the latest CableLabs/Kyrio test is that the "products are nearing feature-complete status" and are being optimized for the level of speeds that D4.0 tech will bring to the market.

Another takeaway is that "DOCSIS 4.0 technology will compete with 10 gigabit passive optical network (PON) solutions that max out at about 8.5 Gbps downstream," Jones added.

"DOCSIS 4.0 technology won't only surpass that speed but will also provide more throughput to the neighborhood than what is possible with 10 gigabit PON," he wrote. "And lastly, these speeds are available over existing coaxial cable already serving tens of millions of customers around the globe."

Related:Comcast's Nafshi says DAA is critical step in DOCSIS 4.0

Still no DOCSIS 4.0-certified equipment

CableLabs and Kyrio announced nearly a year ago that they were ready to accept products for official DOCSIS 4.0 certification testing, covering both options of the specifications – Full Duplex (FDX) and Extended Spectrum DOCSIS (ESD). Products have been submitted to CableLabs for official D4.0 certification testing. However, CableLabs doesn't identify them until they have passed. As of May 2, CableLabs has yet to grant any D4.0 certifications.

Meanwhile, Comcast has pushed ahead with D4.0 deployments in Atlanta, Colorado Springs and Philadelphia with pre-certified DOCSIS 4.0 modems. In February, Comcast introduced the XB10, a DOCSIS 4.0 gateway powered by Broadcom silicon and outfitted with Wi-Fi 7. Comcast expects to launch the XB10 in the second half of 2024.

Even as D4.0 products make progress, there is also growing interest – particularly among small and midsized operators – in next-generation DOCSIS 3.1 modems and upgraded cable modem termination systems (a scenario sometimes called DOCSIS 3.1+, DOCSIS 3.1 "flex" or "extended" DOCSIS 3.1), which can boost network speed and capacity by utilizing additional OFDM (orthogonal frequency-division multiplexing) channels. Those products could help some operators compete with fiber via their D3.1 networks, possibly delaying the need for a distributed access architecture (DAA) and a full DOCSIS 4.0 network upgrade.

Related:Comcast unveils first DOCSIS 4.0 gateway, tests 'high fidelity video'

Meanwhile, work is also underway to deliver 5G on cable network infrastructure. Light Reading will have much more detail on that development soon.