Cable companies often make it sound like DOCSIS 4.0 is right around the corner. This is the technology upgrade that will increase overall speeds to multiple gigabits while also providing the option for symmetrical speeds.
ATX Networks, a leading manufacturer of electronics for cable companies published the results of a survey in May of cable company executives that shows almost half of cable companies intend to implement DOCSIS 4.0 by the end of 2025. That includes 10% of cable companies that say they have already started the upgrade in 2023.
The upgrade to DOCSIS 4.0 is interesting because vendors are not yet offering gear with a full DOCSIS 4.0 solution. Cable companies seem happy to make a partial upgrade now to get somewhat faster speeds and will likely layer on the rest of the upgrade later.
This says a lot about the mindset of cable companies today. They are being besieged from all directions. The public clearly has formed an opinion that fiber is a superior technology to cable technology. The shift to DOCSIS 4.0 will allow cable companies to claim the same speed capabilities as their fiber competitors. If a cable company can upgrade and serve a small portion of customers with a 2-gigabit broadband subscription, they hope they will have evened the playing field in the marketing battle with fiber providers.
Cable companies are also losing customers at the bottom end of the market to FWA cellular wireless as people settle for slower speeds to get significant price savings. A few cable companies, like Charter, face another big customer loss due to the end of the ACP program.
The survey showed that cable companies are taking different approaches on how to upgrade to DOCSIS 4.0. About one-third of the respondents to the survey said they would be happy to get symmetrical speeds using a network with the overall capacity of 1.2 GHz. This is being referred to as a full duplex (FDX) upgrade) since it will provide symmetrical broadband speeds over an existing 1.2 GHz network. The FDX upgrade will get as much extra speed out of a current cable company network as possible, but it saves cable companies from having to go through the expensive process of updating the outside network and amplifiers.
Other cable companies intend to also upgrade the overall bandwidth capability of the network to 1.8 GHz. This is being referred to as an Extended Spectrum (ESD) upgrade. For those wondering why this is expressed in gigahertz, cable networks operate by using a radio network that is captive within the coaxial cable. The DOCSIS technology assigns different portions of this spectrum to different functions, like delivering broadband or cable TV channels. Cable companies upgrading the overall capacity of the network have significantly increased the overall bandwidth available for broadband.
This is the third annual survey from ATX Networks, and the survey shows that more cable companies are now favoring the FDX upgrade, which will be less costly.
Finally, the survey showed that 15% of the cable companies don’t have plans to upgrade to DOCSIS 4.0. There are some interesting alternate upgrades that can milk faster speeds out of an existing DOCSIS 3.1 network. One intriguing patch is to use a DOCSIS 3.1 headend and connect to DOCSIS 4.0 modems for only the customers who want speeds faster than 1 gigabit. This is being labeled as DOCSIS 3.1 Extended and only involves upgrading modems for customers who are willing to buy the fastest speeds.
There are still cable companies that believe the best option is to convert directly to fiber. For example, Cox is upgrading to fiber in some of its largest markets. But that is by far the most expensive option.
The bottom line is that it’s going to be hard in the future to understand the capability of a local cable market. Cable companies are likely to label all their upgrades as having DOCSIS 4.0, even though the different upgrade paths will create networks with widely different capabilities.