There was a time when it seemed certain that cable companies would have to bite the bullet and spend the money to upgrade to fiber. While there have been some upgrades by cable companies like Cox and Altice, most cable companies seem to be deciding that there is still good life left in DOCSIS cable networks. As you might expect, CableLabs has been quietly working behind the scenes to improve existing HFC technology.
DOCSIS 3.1 networks have become standard across the industry, and it’s now rare to see older technologies except for some small cable companies. Cable companies have been using DOCSIS 3.1 networks to deliver gigabit or faster download speeds, with the top speed depending on the overall size of the bandwidth being utilized in the internal radio network that controls the signal.
The whole cable industry got a shock during the pandemic when it became obvious to many of the millions of students and employees who began working out of homes that the slow upload speeds on DOCSIS 3.1 were a bottleneck. I think the inadequacies of this technology and slow upload speeds are what gave a big jumpstart to the public perception that fiber is far superior to cable technology.
CableLabs and vendors responded to the upload speed bottleneck by introducing two solutions that can add to the upstream portion of the cable network. Labeled as midsplit or highsplit, both solutions require some upgrades in the outside plant electronics, along with upgraded cable modems in homes. The midsplit upgrade is accomplished by increasing the frequencies used to support upload from 5-42 MHz to 5-85 MHz. The highsplit upgrade allocated even more frequency to uploading, as much as 204 MHz. Both of these upgrades increased upload speeds to 100 Mbps or faster, which eliminated the bottleneck for the average customer. In 2025, CableLabs offered an even better version of the midsplit upgrade by offering a new cable modem that can handle up to four more channels of bandwidth.
CableLabs is also improving DOCSIS 4.0 technology. This is an upgrade that became available for cable companies in early 2024 that can provide symmetrical broadband speeds. While the upgrade can deliver speeds up to 5 Gbps, most cable companies are using it to offer symmetrical 2 Gbps broadband. This upgrade makes it practical for a cable company to say it can match fiber speeds – or at least it did in 2024. There are now fiber ISPs offering residential broadband at speeds up to 10 Gbps.
CableLabs has demonstrated an upgrade to DOCSIS 4.0 that can mimic the faster advertised speeds of fiber providers. CableLabs recently released a new standard it is calling DOCSIS 4.0 Optional Annex. This standard works by increasing the network bandwidth inside the coaxial cable to 3 GHz. Cable networks operate by using radio frequencies inside the coaxial wires. Most DOCSIS 3.1 networks use 1.0 to 1.2 of total frequency. Some companies have upgraded to 1.6 GHz for DOCSIS 4.0. This new optional Annex, double that bandwidth and will supposedly support speeds up to 25 Gbps. CableLabs is also looking at a version of the new technology that would increase total network bandwidth to 6 GHz, which might support broadband speeds up to 50 Gbps.
These new options will give pause to any cable company thinking about upgrading to fiber. These new technologies provide a realistic alternative to fiber with DOCSIS 4.0.