Looking ahead: Next-gen broadband networks aim for speed with DOCSIS 4.0 and PON

The next chapter in cable and fiber networks will see cable operators focus on a new phase of their widely deployed hybrid fiber/coax (HFC) networks as telcos – and some cable operators – maintain their pursuit of speedier passive optical network (PON) and Ethernet technologies.

DOCSIS 4.0 represents the next generation of HFC, enabling symmetrical multi-gigabit speeds, enhanced security and lower latency. The products and technologies that will underpin DOCSIS 4.0 are expected to mature in the coming year as modem makers start to develop devices that are powered by a new generation of chipsets. That includes the Puma 8 chip from MaxLinear, which supports the Extended Spectrum DOCSIS (ESD) option of D4.0, along with a unified chip from Broadcom (with help from Comcast) that's made to support both flavors of DOCSIS 4.0: ESD and Full Duplex (FDX).

Out on the network, expect suppliers to continue pushing amplifiers and other outside plant equipment focused on 1.8GHz technology – a key component of future D4.0 upgrades that will utilize the ESD option. A big question heading into the year is how quickly cable operators will start to adopt and deploy 1.8GHz technology in a meaningful way.

On the FDX side, CommScope is expected to make progress with the FDX amplifier, a key component of Comcast's plan to deploy DOCSIS 4.0 across the vast majority of its footprint.

As deployments go, Comcast will continue to lead the way, building on its initial D4.0 deployments in Atlanta, Colorado Springs and Philadelphia and expanding on the launch of a new array of "X-Class Internet" tiers that offer symmetrical speeds up to 2 Gbit/s.

Following a series of field trials that got underway in 2023, Comcast is also expected to be among the first cable operators to deploy Low Latency DOCSIS, an enhancement that could be attractive to certain segments of the market such as competitive online gamers.

Extending the life of DOCSIS 3.1

But DOCSIS 4.0 won't be for all operators, at least not right away.

As 2023 came to a close, it was clear there was growing interest among North American and European cable operators for an "extended" or "boosted" form of DOCSIS 3.1 that can help them mine more speed out of their legacy D3.1 networks. MaxLinear and Broadcom are both getting behind that effort at the chip level, setting the stage for this enhanced version of D3.1 to become a bigger story in 2024, possibly turning D4.0 into a potential sideshow.

Pondering what's next for PON

Expect an even bigger rush among telcos toward XGS-PON as the running option. But there should also be some additional movement for more advanced forms of the technology as some fiber service providers put more focus on speeds that exceed 10 Gbit/s and expand their pursuit of 25G PON technology.

Telcos might also be thinking beyond that. Some industry experts view 25G PON as current generation technology and consider 100G as the next big step forward.

And expect more instances where PON is not the primary part of the picture. A recent example is Ziply Fiber, which is using Ethernet connections to power a new (and very targeted) 50 Gbit/s residential broadband service that sells for a lofty price of $900 per month.

Cable will also be getting into the fiber act in a bigger way. Fiber and PON have become a major focus at CableLabs, which is pushing ahead with a pair of fiber-focused working groups, including one that will explore a DOCSIS framework for provisioning ITU-based PON standards, including XGS-PON.

Those projects are coming together as cable operators continue to put PON in their arsenals for targeted deployments off of fiber nodes and broader greenfield deployments, including various rural buildout projects aided by government funding programs. According to a recent Omdia survey, about 35% of cable operators have already deployed PON in their networks, with another 47% percent expected to do so within the next year. Omdia is a sister company to Light Reading.