The DOCSIS vs. Fiber Debate

In a recent article in FierceTelecom, Curtis Knittle, the VP of Wired Technologies at CableLabs, argues that the DOCSIS standard is far from over and that cable company coaxial cable will be able to compete with fiber for many years to come. It’s an interesting argument, and from a technical perspective, I’m sure Mr. Knittle is right. The big question will be if the big cable companies decide to take the DOCSIS path or bite the bullet and start the conversion to fiber.

CableLabs released the DOCSIS 4.0 standard in March 2020, and the technology is now being field tested in planned deployments through 2022. In the first lab deployment of the technology earlier this year, Comcast achieved a symmetrical 4 Gbps speed. Mr. Knittle claims that DOSIS 4.0 can outperform the XGS-PON we’re now seeing deployed. He claims that DOCSIS 4.0 will be able to produce a true 10-gigabit output while the XGS-PON actual output is closer to 8.7 Gbps downstream.

There are several issues that are going to drive the decision-making in cable company board rooms. The first is cost. An upgrade to DOCSIS 4.0 doesn’t sound cheap. The upgrade to DOCSIS 4.0 increases system bandwidth by working in higher frequencies – similar to G.Fast on telephone copper. A full upgrade to DOCSIS 4.0 will require ripping and replacing most network electronics. Coaxial copper networks are getting old and this probably also means replacing a lot of older coaxial cables in the network. It probably means replacing power taps and amplifiers throughout the outside network.

Building fiber is also expensive. However, the cable companies have surely learned the lesson from telcos like AT&T and Verizon that there is a huge saving in cost by overlashing fiber onto existing wires. The cable company can install fiber for a lot less than any competitor by overlashing onto existing coax.

There is also an issue of public perception. I think the public believes that fiber is the best broadband technology. Cable companies already see that they lose the competitive battle in any market where fiber is built. The big telcos all have aggressive plans to build fiber-to-the-premise, and there is a lot of fiber coming in the next five years. Other technologies like Starry wireless are also going to nibble away at the urban customer base. All of the alternative technologies to cable have faster upload speeds than the current DOCSIS technology. The cable industry has completely avoided talking about upload speeds because they know how cable subscribers struggled working and schooling from home during the pandemic. How many years can the cable company stave off competitors that offer a better experience?

There is finally the issue of speed to market. The first realistic date to start implementing DOCSIS 4.0 on a large scale is at least five years from now. That’s five long years to limp forward with underperforming upload speeds. Customers that become disappointed with an ISP are the ones that leap first when there is any alternative. Five years is a long time to cede the marketing advantage to fiber.

The big cable companies have a huge market advantage in urban markets – but they are not invulnerable. Comcast and Charter have both kept Wall Street happy by seeing continuous growth from the continuous capture of disaffected DSL customers. Wall Street is going to have a totally different view of the companies if that growth stops. The wheels likely come off stock prices if the two companies ever start losing customers.

I’ve always thought that the cable’s success for the last decade has been due more to having a lousy competitor in DSL than it has been by a great performance from the cable companies. Every national customer satisfaction poll continues to rank cable companies at the bottom behind even the IRS and funeral homes.

We know that fiber builders do well against cable companies. AT&T says that it gets a 30% market share in a relatively short time everywhere it builds fiber. Over time, AT&T thinks it will capture 50% of all subscribers with fiber, which means a 55% to 60% market share. The big decision for the cable companies to make is if they are willing to watch their market position start waning while waiting for DOCSIS 4.0. Are they going to bet another decade of success on aging copper networks? We’ve already seen Altice start the conversion to fiber. It’s going to be interesting to watch the other big cable companies wrestle with this decision.

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