DOCSIS 4.0: Ushering in the Next Generation of Cable Internet

May 2019

As the demand for faster, more reliable internet continues to surge, the cable industry is stepping up with a powerful new standard: DOCSIS 4.0. Short for Data Over Cable Service Interface Specification, DOCSIS 4.0 represents a major leap forward in broadband technology, promising multi-gigabit speeds and enhanced network efficiency. But what exactly is DOCSIS 4.0, and why is it such a big deal?

What Is DOCSIS?

DOCSIS is the technology that enables high-speed internet over existing coaxial cable TV systems. Developed by CableLabs, it has evolved through several generations:

• DOCSIS 1.0/1.1: Introduced basic broadband over cable.
• DOCSIS 2.0: Improved upstream speeds.
• DOCSIS 3.0: Brought channel bonding for faster speeds.
• DOCSIS 3.1: Enabled gigabit-class speeds and better spectrum efficiency.

Now, DOCSIS 4.0 is here to take things even further.

What’s Special About DOCSIS 4.0?

DOCSIS 4.0 introduces several groundbreaking features that set it apart from its predecessors, and adoption varies by provider and by OEMs providing the hardware.  In many cases, a unified set of deployment options is being offered by vendors such as Harmonic and their CableOS solution:

1. Multi-Gigabit Symmetrical Speeds

DOCSIS 4.0 supports up to 10 Gbps downstream and 6 Gbps upstream - a massive upgrade, especially on the upload side. This is crucial for modern applications like video conferencing, cloud gaming, and remote work, as well as for end-user customers and businesses utilizing hosted applications.

2. Full Duplex Communication

One of the most revolutionary aspects of DOCSIS 4.0 is Full Duplex DOCSIS (FDX). This allows data to be sent and received simultaneously over the same spectrum, significantly boosting upstream capacity without sacrificing downstream performance.

3. Extended Spectrum DOCSIS (ESD)

DOCSIS 4.0 expands the usable spectrum up to 1.8 GHz, compared to 1.2 GHz in DOCSIS 3.1. This means more bandwidth and better performance, especially in densely populated areas. It also means that existing hardware within the network needs to be replaced to handle the “High-Split” and “Ultra High Split” frequencies.

4. Improved Latency and Reliability

With enhanced scheduling and error correction, DOCSIS 4.0 reduces latency and improves overall network reliability—key for real-time applications like online gaming and video calls.

5. Backward Compatibility

DOCSIS 4.0 is designed to work with existing DOCSIS 3.1 infrastructure, allowing cable operators to upgrade gradually without overhauling their entire network. As mentioned above, certain network equipment does need to be replaced to handle the different frequencies being used by DOCSIS 4.0.

Why It Matters

As fiber-optic networks continue to expand, DOCSIS 4.0 ensures that cable providers remain competitive by delivering fiber-like performance over existing infrastructure. This means faster internet for more people, without the need for disruptive and costly rewiring. Cable operators can leverage investments made over many years in the coaxial (HFC) network, deploying higher-speed services more easily than building out a new fiber-optic network, for example.

When Will It Be Available?

DOCSIS 4.0 hardware is beginning to roll out now, and competitive pressure will drive growth. Cable operators are currently testing and deploying DOCSIS 4.0-compatible equipment, with broader availability expected over the next few years.

In Summary: DOCSIS 4.0 is a game-changer for cable broadband, offering blazing-fast speeds, better upload performance, and future-ready technology. It’s a key step toward meeting the ever-growing demands of the digital age.

If your company needs to test DOCSIS 4.0 equipment, please contact Promptlink here to find out how to get your existing system ready for DOCSIS 4.0 or to acquire a ready-made system for CPE testing.