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Technology Types

DOCSIS 4.0

The newest cable internet standard that promises multi-gigabit symmetrical speeds over existing coaxial cable infrastructure, closing the performance gap with fiber.

What It Means

DOCSIS 4.0 is the cable industry's response to the FTTH threat, an upgrade to the DOCSIS specification published by CableLabs in March 2020 that pushes maximum downstream capacity to 10 Gbps and upstream to 6 Gbps over existing coaxial cable. Two distinct approaches compete under the DOCSIS 4.0 umbrella: Full Duplex DOCSIS (FDX), favored by Comcast, allows simultaneous upstream and downstream transmission on the same frequencies, and Extended Spectrum DOCSIS (ESD), favored by Charter and Cox, expands the usable frequency range up to 1.8 GHz to create new upstream capacity. Both approaches deliver symmetrical multi-gigabit service, matching the core performance promise of fiber-to-the-home. Comcast launched its first DOCSIS 4.0 markets in Colorado Springs, Atlanta, and Philadelphia in late 2023 and plans to cover more than 50 million passings by the end of 2026. The strategic advantage of DOCSIS 4.0 is capital efficiency: upgrading existing hybrid fiber-coax plant to DOCSIS 4.0 costs roughly $100 to $200 per home passed, versus $500 to $2,000 per home passed for fiber overbuild. This 5 to 10x cost advantage is why cable operators can continue to defend their roughly 55% market share even as fiber deployment accelerates. For the Broadband Grade, DOCSIS 4.0 availability counts fully toward the download speed score (40% of grade) but does not count as fiber availability (20% of grade).

Frequently Asked Questions

What does "DOCSIS 4.0" mean?

The newest cable internet standard that promises multi-gigabit symmetrical speeds over existing coaxial cable infrastructure, closing the performance gap with fiber.

Why does DOCSIS 4.0 matter for internet quality?

DOCSIS 4.0 is the cable industry's response to the FTTH threat, an upgrade to the DOCSIS specification published by CableLabs in March 2020 that pushes maximum downstream capacity to 10 Gbps and upstream to 6 Gbps over existing coaxial cable. Two distinct approaches compete under the DOCSIS 4.0 umbr...

Related Terms

Fiber Optic (FTTH)
Internet delivered via glass or plastic strands that transmit data as pulses of light, offering the fastest and most reliable residential connections available.
Cable Internet (DOCSIS)
Broadband delivered over coaxial cable TV lines using the DOCSIS protocol, typically offering 100-1,200 Mbps download but significantly slower upload speeds.
DSL (Digital Subscriber Line)
Internet service delivered over traditional copper telephone lines, with speeds that degrade significantly over distance from the provider's central office.
Fixed Wireless Access (FWA)
Broadband delivered wirelessly from a cell tower or base station to an antenna at the customer's location, using 4G LTE or 5G signals.

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About This Data

Definitions based on FCC standards, industry specifications, and federal broadband policy. Speed benchmarks reflect 2024 FCC standards. See our methodology.

this entity is one of the U.S. internet availability and broadband speed concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the FCC Broadband Data Collection (BDC) data behind every per-entity page on the site.

In the the FCC Broadband Data Collection (BDC) data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.

Source: FCC Broadband Data Collection, 2026.