Optical Networking, Redefined.
June 27, 2023

Unleashing the Potential of DOCSIS 4.0: Advantages and Infrastructure Challenges

Even though a broad rollout of DOCSIS 4.0 will not start until 2024 or 2025 (some optimistically talk about late 2023), it’s never too early to start thinking about the future and what kind of impacts this new standard will have on your networks. Increasing interest in enhanced downstream and upstream performance to satisfy the bandwidth and speed demands of their end-users is driving HFC network operators to look to DOCSIS 4.0, the next generation of data-over-cable transmission standards. Today, we’ll dive deeper into why network operators are eager to upgrade to DOCSIS 4.0, highlighting its projected advancements over DOCSIS 3.1 and shedding light on some of the infrastructure challenges they will face during the transition. 

DOCSIS 4.0 vs DOCSIS 3.1: Unveiling the Advantages 

DOCSIS 4.0 represents a significant leap forward compared to its predecessor, DOCSIS 3.1. Let’s explore the key advantages that make DOCSIS 4.0 an attractive choice for MSOs, MNOs and other providers with HFC networks. 

  1. a) Unprecedented Speed and Bandwidth

DOCSIS 4.0 sets new benchmarks in speed and bandwidth capabilities. With a downstream capacity of up to 10 Gbps and an upstream capacity of up to 6 Gbps, it will support the ever-growing performance demands of bandwidth-intensive applications such as 4K/8K video streaming, cloud-based services, and emerging technologies like virtual reality and augmented reality. Compared to DOCSIS 3.1, which only offers an upstream capacity of 1-2 Gbps despite also providing downstream capacity of 10 Gbps, DOCIS 4.0 holds a lot of promise. 

  1. b) Enhanced Spectrum Efficiency

DOCSIS 4.0 also introduces advanced technologies that optimize spectrum utilization. Here’s how. First, DOCSIS 4.0 comes in two variants: Full Duplex (FDX) and Extended Spectrum (ESD). FDX prioritizes downstream bandwidth, enabling the transmission of both downstream and upstream spectrum on top of one another. Since previous DOCSIS 3.1 and 3.0 standards did not enable this, FDX essentially doubles spectral efficiency. With DOCSIS 4.0 FDX, however, the downstream spectrum upper limit remains the same as in DOCSIS 3.1 at 1.2 GHz.[Text Wrapping Break][Text Wrapping Break]For its part, DOCSIS 4.0 ESD essentially shifts the downstream spectrum upper limit from 1.2 GHz to 1.8 GHz, enabling the upstream spectrum to extend past DOCSIS 3.1’s limit of 204 MHz up to 684 MHz. Downstream spectrum is still run above the upstream spectrum, but now punching past the limitations of previous DOCSIS standards. In the media, Charter Communications has reported that, in lab tests, they’ve been able to push the downstream spectrum upper limit to as high as 3.2 GHz. By either doubling the efficiency of existing spectrum or overcoming previous upper limits, DOCSIS 4.0 FDX and ESD will enable HFC network operators to improve their ability to compete with FTTH architectures, which feature end-to-end fiber connectivity. 

  1. c) Low Latency and Improved Quality of Experience

Low latency is integral to DOCSIS 4.0. The standard will be able to reduce latency (the time it takes for data to travel along a network) to under 1 millisecond and maintain latency speeds under 5 milliseconds on a fully saturated network. Reduced latency will be crucial for the simultaneous use of real-time applications like online gaming, video conferencing, video streaming and IoT deployments. DOCSIS 4.0 promises to deliver the enhanced quality of experience that end-users require, further helping HFC network operators do more with their networks.  

Infrastructure Upgrades: Optical Transceivers 

While upgrading to DOCSIS 4.0 presents numerous benefits, HFC network operators must also contend with advancements in the FTTH PON sector that are enabling it to push past symmetrical 10 Gbps to 25 and even 50 Gbps services. Already, HFC network operators have a pathway to 10 Gbps with DOCSIS 3.1, so the pressure is mounting from potential DOCSIS 4.0 adopters to achieve 25 Gbps DOCSIS. As Fierce Telecom noted, CableLabs, the group behind the DOCSIS specifications, has said that “there are no fundamental limitations for why cable can’t be symmetric just like PON.” This has already prompted discussion around the idea of ESD DOCSIS 4.0 at 1.8 GHz, forming a launch pad for eventual 3 GHz, 25G ESD DOCSIS 4.0. Moving towards this, however, will require forward-thinking infrastructure upgrades, especially in the access network. 

As network operators seek to do more with their existing infrastructure (like pursuing DOCSIS 4.0), enabling higher data rates to the edge is becoming a critical requirement. Unfortunately, current 25G DWDM optical transceiver solutions leave a gap between link distance and performance: while current 10G DWDM transceivers can enable transmission distances of up to 80km, existing 25G DWDM options limit network operators to 10-15km unless specialized equipment is used. Given that most access network links are up to 80km, this poses a challenge for those network operators beginning to look towards future implementation of DOCSIS 4.0 and/or ESD DOCSIS 4.0. 

The pathway toward DOCSIS 4.0 requires strategic partnerships. Network operators need more than equipment manufacturers. They need partners with deep-seated engineering expertise, rigorous lab and field-testing capabilities and systems integration expertise to address issues around performance and interoperability. Here at Precision OT, we have this in spades. As today’s HFC network operators begin looking into the future, we’re here to help them make their journeys simpler. Reach out to our team of engineers today with your questions – if there’s a challenge, we can help you solve it!