A Fork in the Road to DOCSIS 4.0 Emerges
Many businesses, consumers, and network providers rely on the Data Over Cable Service Interface Specification (DOCSIS) for their broadband services. This network option, which has been popular for decades, has periodically gained new capabilities in a seamless fashion. However, this is not the case with its latest iteration, DOCSIS 4.0. A split and incompatible standard has emerged – a two pronged fork leading to different camps which are expected to deliver compliant products during 2024. So, which iteration will become more popular, a focus on higher download speeds, or a balance that considers uploads as well?
Since its inception in the late 1990s, DOCSIS has been the backbone of broadband over cable networks business and home services. Many cable TV providers use it to deliver high speed Internet access over coaxial cabling to their customers.
The standard remains popular today. In the US, it accounts for 50% of broadband home connections. The global DOCSIS and Cable Modems market is expected to reach $9.57 billion in 2028, according to Reports and Data.
Customers Demand Faster Internet Access
Did you know that slow video buffering was actually normal just a few years ago. Try telling that to today’s young consumer; sounds like a bad myth. Interest in faster network speeds is an exponentially growing black hole with no end in sight.
So, network equipment suppliers and cable providers have to keep delivering new versions of DOCSIS that enhance network speeds, capabilities, and the overall efficiency. The last iteration of the standard, DOCSIS 3.1. was delivered back in 2013 and provided a bandwidth boost to the Gbps (Gigabits per second) range.
Work on DOCSIS 4.0 began in 2017. One major goal they set to achieve was creating symmetric data transmissions – a feature cable modem historically lacked. Traditionally, cable modem download speeds have been much faster than their upload capabilities. Past versions relied on separate upload and download connections. Why?
Typically, users download more information than they upload. Consequently, cable companies used the highest throughput and least likely interference parts of the link for downloads. Uploads were sent via the less stable frequency ranges.
DOCSIS 3.1 has roughly a 10:1 ratio between its download and upload capacities. Successive versions of the standard were designed to change that.
DOCSIS Standards
| DOCSIS 3.1 | DOCSIS 4.0 Full Duplex | DOCSIS 4.0 ESD | |
|---|---|---|---|
| Downstream | 10 Gbps | 10 Gbps | 10 Gbps |
| Upstream | 1 Gbps | 6 Gbps | 6 Gbps |
| Frequency Range | 10 MHz to 1.794 MHz | 258 MHz to 1794 MHz | 258 MHz to 2.974 MHz |
| Key Features | Faster speed | Symmetrical streaming | Symmetrical streaming |
With DOCSIS 4.0, two incompatible approaches (Full Duplex DOCSIS and Extended Spectrum DOCSIS) emerged to boost its capacity and upload capabilities.
Full Duplex DOCSIS allows for simultaneous data transmission in both the upstream and downstream directions. Here, transmissions work in frequency ranges up to 1.8 GHz. This emerging specification increases network capacity by utilizing the existing spectrum more efficiently, resulting in improved performance and reduced contention.
The Full Duplex version has gained support from equipment manufacturers and network providers. A notable partnership in the broadband internet realm is that between Qualcomm and Comcast. Qualcomm is a leading DOCSIS chipmaker while Comcast completed a successful field trial in Philadelphia and has been putting together plans for broad service release, which is expected to be rolled out during the next few years.
Technological Bifurcation
Extended Spectrum DOCSIS which has been referred to as DOCSIS 3.5, uses wider frequency ranges for data transmissions, 1.8 GHz to 3 GHz. The extended frequency range provides more bandwidth as well as the symmetrical high speed coaxial cable capabilities found with Full Duplex DOCSIS.
Interest in the upgrade ESD path has also been growing. Operators like Charter Communications, have begun conducting lab trials and planning for limited deployments and eventually full-scale availability.
What’s Next?
It’s evident that the next upgrade has begun with many uncertainties. Initially, both standards seem as if they will gain some market momentum because they are backed by key industry suppliers. In the short term, carriers will face a choice of using one or the other. Since both operate in different frequency ranges, they will not be interoperable.
Also, any time that a new standard emerges, a transition occurs as a new ecosystem has to be created. The process starts from the ground up with microprocessors and accompanying software that support the emerging network protocols and includes other components, like network equipment and management tools.
Impact on Service Provider Headend
In this case, the move to 10G symmetrical transmissions is expected to require cable network upgrades. Headend upgrades are very unpopular with broadband cable providers, hence the resistance to 4.0 and some initial interest in 3.5. However, headend changes are likely inevitable in both cases. The new specification’s higher bandwidth means that many cable companies will need to upgrade the fiber infrastructure that collects transmissions and sends them over the Internet. Upgrades to service provider’s headend infrastructure and coaxial cabling is expected to be in the $100 to $200 per subscriber home range.
Network upgrades costing a few hundred dollars will be needed with DOCSIS 4.0. In addition, carriers must extend their network monitoring and troubleshooting tools. They need to develop solutions that overcome potential issues, such as signal interference, on the new connections.
Moreover, the transition to DOCSIS 4.0 is not just a technical upgrade but also an operational one. Staff will need to be trained in the similarities and differences that the new networking option possesses.
Still, even more ambiguity and risk looms. In the short term, the two alternatives will not interoperate. Longer term, the industry could develop ways to meld the two. Organizations like CableLabs and SCTE as well as network operators, and equipment vendors are working together to share knowledge and develop capabilities and tools for the new deployments.
Best Move to Make?
Given the wide-ranging uncertainty, what should cable service suppliers, equipment providers, and third parties do to minimize the potential confusion? They need to understand the technology nuances that are arising. They need to find and work with vendors that have flexible solutions that ideally support both options gracefully. In addition, their partner(s) should have a great deal of experience in the broadband cable Internet market.
embedUR has been working with companies that deliver DOCSIS products and services for more than a decade. We know the standard inside out. Let us limit the impact that schisms such as this one have on your networking solutions.
To learn how embedUR can help you navigate the choppy DOCSIS waters, talk to us and share your ideas with us for the best strategy and outcome.
