Tag Archives: DOCSIS 3.0

DOCSIS 3.0 is Obsolete

Most State Broadband Offices have decided that DSL is an obsolete technology, regardless of the bandwidth that it can deliver. This means that for purposes of BEAD grants, homes and businesses served by DSL are considered to be unserved even when the DSL is providing speeds greater than 25/3 Mbps (underserved) or 100/20 Mbps (served).

The reasons for ignoring DSL for purposes of BEAD is that DSL is an obsolete technology. Copper networks are old and dying. Telcos are working diligently to back out of the copper business. Even where DSL might still be working well for customers today, nobody expects those connections to still be functioning a decade from now. States want to make sure that customers whose only choice today is DSL will have a broadband option going into the future.

I think that NTIA and the States should make the same determination for cable networks still using DOCSIS 3.0 technology. There are still a number of small towns and cities where cable networks are deployed with this technology.

DOCSIS technology (Data Over Cable Interface Specification) was created by CableLabs to give cable companies the ability to deliver broadband over a hybrid fiber-coaxial network. There have been several generations of DOCSIS technology. The first generation of the technology was DOCSIS 1.0, released in 1997. This technology allowed cable companies to offer broadband download speeds of 1 Mbps, and was eventually used to boost download speeds to around 6 Mbps broadband.

This was quickly followed by DOCSIS 2.0, released in 2001. This upgrade allowed for more channels to be assigned to broadband and was used over time to offer speeds up to 60 Mbps download. DOCSIS 3.0 was a significant upgrade that allowed the bonding of multiple channels together for the broadband path. This allowed cable companies to increase download bandwidth to several hundred Mbps. But most DOCSIS 3.0 networks have upload speeds under 20 Mbps.

The most commonly deployed configuration of HFC technology in the U.S. is DOCSIS 3.1. This was the upgrade that introduced gigabit download capability. This is the technology deployed in every major city and in most smaller cities and towns. The cable industry is already conducting trials of DOCSIS 4.0. This upgrade will allow for speeds of 5 Gbps download and will also allow for upload speeds of several Gbps. This is the upgrade that cable companies hope will allow them to compete on an even footing with fiber.

It’s not hard to make an argument that DOCSIS 3.0 is obsolete. The technology will soon be two generations of technology behind what will be deployed in most markets. The vast majority of cable customers in the country have already seen an upgrade to DOCSIS 3.1 which brought the ability to buy gigabit speeds. Nobody expects DOCSIS 3.0 networks to still be functioning a decade from now. Any cable company operating this technology will have to eventually upgrade – but until they do, this technology should not qualify for BEAD funding.

It’s possible to tweak and fine-tune a DOCSIS 3.0 network to just squeak by as served for BEAD grants. But in my mind, counting DOCSIS 3.0 as served is equivalent to letting telcos still claim DSL as served.

It won’t take many years for a DOCSIS 3.0 network to degrade in capability as customers use more broadband each year. I always refer back to Open Vault statistics that show that the average usage for broadband customers has increased from 270 gigabytes per month at the end of 2018 to 641 gigabytes per month at the end of 2023. It’s inconceivable to think that a DOCSIS 3.0 network will be able to handle the broadband loads that are coming just a decade from now. That’s the primary reason why the technology is obsolete. If networks with DOCSIS 3.0 technology are classified as providing adequate broadband today, the owners of these networks will have no incentive to make investments to improve the networks.

I’m sure that a decade ago, nobody would have believed that there would be telcos still claiming 100/20 Mbps broadband speeds for DSL today – but I’ve seen pockets of this across the country. State Broadband Offices and the NTIA have recognized that the technology is not sustainable to meet future broadband needs and decided to ignore DSL when defining BEAD-eligible locations. If they apply the same logic to DOCSIS 3.0 networks, I’m positive they will draw the same conclusion.

Will Cable Companies Tackle Faster Upload Speeds?

The number one complaint I’ve been hearing about broadband during the pandemic is that people found that they were unable to conduct multiple online sessions for working or doing schoolwork from home. I’ve talked to a lot of people who have been taking turns using broadband, which is an unsatisfactory solution for everybody involved. This phenomenon became instantly apparent for people with slow rural broadband connections, but a lot of people in towns using cable company broadband hit the same roadblock.

Cable companies have always been stingy with upload speeds because it hasn’t really mattered to the public. Only a handful of customers who wanted to upload large data files ever cared much about upload speeds. But connecting to a school or work server or talking on Zoom requires dedicated upload connections – and when those functions suddenly became a part of daily life, people suddenly cared a lot about upload broadband speeds.

By now, most cable companies have upgraded their networks to DOCSIS 3.1. This allowed upgrades of download speeds from a maximum of perhaps 200 Mbps up to a gigabit. Unfortunately, as part of this upgrade, many cable providers did nothing to improve upload speed.

People may not realize that the signals inside of a cable company network use radio frequencies to transmit data, meaning a cable network is essentially a captive radio network kept inside of the copper coaxial wires. As such, the signals inside a coaxial system share the same characteristics as any wireless network. Higher frequencies carry more data bits than lower frequencies. All of the signals are subject to interference if external frequencies leak into the cable transmission path.

The DOCSIS specification for cable broadband sets aside the lowest frequencies in the system for upload bandwidth – the spectrum between 5 MHz and 42 MHz. This happens to be the noisiest part of cable TV frequency – it’s where outside sources like appliances or motors can cause interference with the signal inside the cable network.

The DOCSIS 3.0 specification, released in 2006 allowed for other parts of the spectrum to be used for upload data speeds, but very few cable companies took advantage of the expanded upload capability, so it’s laid dormant. This DOCSIS 3.0 standard allowed a mid-split option to increase the frequency for upload to 85 MHz. or a more-aggressive high-split option to assign all of the bandwidth up to 204 MHz to data upload. DOCSIS 4.0 is going to offer even a wider range of upload speeds, as high as 684 MHz of spectrum.

It’s been widely reported during the pandemic that millions of households have upgraded to faster broadband packages in hopes of solving the upload problem. But upgrading download speed from 100 Mbps to 200 Mbps won’t help a household if the upload path is the same with both products.

Cable companies are faced with a big cost dilemma. It’s costly to upgrade a cable network from today’s stingy upload speeds to the mid-spit or hi-split option. Rearranging how the bandwidth is used inside of a cable network means replacing many of the key components of the network including neighborhood nodes, amplifiers, and power taps. It could mean replacing all cable modems.

It’s hard to know what cable companies will do. They might be hoping that the issue blows over when people and students move back out of the home. And to some extent that could happen. We saw the average monthly download bandwidth used by homes drop this year from 404 gigabytes in March to 380 gigabytes in June after home-schooling ended for the spring school year. There is likely going to be some relief for upload bandwidth demand when the pandemic is finally over.

But there is a lot of evidence that the increased demand for upload bandwidth will never drop to pre-pandemic levels. It seems likely that millions of jobs are going to permanently migrate to the home. It seems likely that schools will more freely allow students with illnesses to keep up with schoolwork remotely.  High school students are likely to see more options for advanced placement classes online. It looks like video conferencing is here to stay.

Will cable companies make a big investment just to improve upload speeds? Most of don’t plan to upgrade to DOCSIS 4.0 until near to the end of this decade and might decide to spend no other capital until then – since that future upgrade will mean replacing all components of the network again. The cable companies have the ability to greatly increase upload speeds today – but my bet is that almost none of them will do so.