Cable broadband providers are under pressure as fixed wireless access gains most of the new broadband customers and fiber-to-the-home continues to deliver faster, more reliable service. To stay competitive, major cable operators in the U.S. are upgrading their networks with technologies such as DOCSIS 3.1 and 4.0 and reallocating spectrum through mid-split and high-split configurations to boost upload speeds and reduce latency.
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Kerry Baker at Ookla said: “These upgrades represent the most significant architectural change to the cable network in over a decade. They are the essential groundwork for DOCSIS 4.0, which promises to finally deliver the symmetrical, multi-gigabit speeds needed to achieve performance parity with fiber.”
Comcast is pursuing broad nationwide mid-split upgrades to prepare for DOCSIS 4.0, while Charter is focusing on targeted high-split deployments for rapid speed gains. These upgrades, confirmed by rising median upload speeds in Ookla Speedtest data from 2024 to 2025, lay the groundwork for future symmetrical, multi-gigabit service as consumer demand for high-performance gaming, video conferencing, and streaming continues to grow.
The latest Ookla report has highlighted the performance of cable operators such as Comcast, Charter, Cox Communications, Altice (Optimum),
Comcast is executing a sweeping nationwide mid-split upgrade that has significantly boosted upload speeds across its network and set the stage for DOCSIS 4.0. Speedtest data show that median upload speeds in most markets jumped from about 23–24 Mbps in Q2 2024 to around 40–42 Mbps in Q2 2025, a 75–80 percent increase, reflecting the expanded upstream spectrum of the mid-split architecture.
This uniform rollout supports Comcast’s Project Genesis initiative and positions the company to deliver future symmetrical multi-gigabit service. Colorado Springs stands out with a rise from 36.42 Mbps to 63.86 Mbps, suggesting early DOCSIS 4.0 deployment, consistent with Comcast’s announcement naming the city as one of its first “X-Class” launch markets. Atlanta and Philadelphia, also early launch cities, currently show mid-split-level speeds, indicating a limited initial DOCSIS 4.0 footprint.
Charter is rolling out high-split network upgrades in select markets, driving dramatic improvements in upload speeds and signaling the first phase of its network evolution strategy. Speedtest data from Q2 2024 to Q2 2025 show jumps of five- to nine-fold in key areas such as Dallas/Fort Worth and Kentucky, matching Charter’s announced high-split deployments.
Reno, an early upgrade site, recorded a sixfold speed increase before mid-2024, already surpassing 100 Mbps uploads. Most major cities, including Los Angeles and New York, still show legacy sub-split performance around 21 Mbps, consistent with Charter’s statement that only about 15 percent of its footprint has completed “Step 1” of the upgrade plan, leaving significant room for expansion and potential multi-hundred-megabit upstream speeds.
Cox Communications is pursuing a phased network upgrade strategy that blends mid-split and high-split deployments to prepare for DOCSIS 4.0. Speedtest data show three stages of enhancement: initial mid-split upgrades that roughly double legacy sub-split upload speeds, as seen in Gainesville, Florida (16.47 to 34.97 Mbps) and New Orleans, Louisiana (11.51 to 23.76 Mbps); mid-split maturation with moderate gains in markets like Phoenix, Arizona (53.71 to 58.11 Mbps); and high-split upgrades pushing upload speeds toward or above 100 Mbps. This multi-stage approach allows Cox to spread capital investment while steadily improving upstream performance and positioning its network for future symmetrical multi-gigabit service, even as it heads toward a planned merger with Charter in 2026.
Jeff Heynen at Dell’Oro Group in a report said that Charter and Cox are advancing Distributed Access Architectures with virtual CMTS (vCMTS) and Remote PHY devices to modernize their cable networks. Charter is in the early stages of Remote PHY deployments, while Cox has already converted nearly all optical nodes to Remote PHY after migrating from Cisco’s M-CMTS platforms to a CCAP-based setup.
Cox is now adopting Vecima’s vCMTS platform to fully leverage Ethernet transport between the headend and RPDs. Both operators plan to use the Extended Spectrum version of DOCSIS 4.0, but Charter aims for an earlier rollout as it upgrades its spectrum from 750 MHz to 1.2 GHz with high-split architecture, whereas Cox, already operating most of its network at 1 GHz with mid-split, is moving more gradually toward DOCSIS 4.0, Jeff Heynen said.
Altice (Optimum) is taking a hybrid approach by incrementally enhancing its DOCSIS 3.1 cable network while aggressively expanding fiber-to-the-home to achieve future multi-gigabit speeds. Speedtest data show stable upload performance of 25–35 Mbps across Optimum markets from Texas to New Jersey, with no significant mid-split or high-split upgrades, such as New York’s modest rise from 25.14 Mbps to 29.13 Mbps.
In its Q2 2025 earnings report, the company said mid-split upgrades will enable multi-gigabit service on parts of its HFC network starting in 2026, aiming to deliver multi-gig speeds to 65 percent of its footprint by 2028. This strategy balances limited cable enhancements with targeted fiber buildouts to create a more future-proof network.
Baburajan Kizhakedath
