AT&T vs Verizon vs T-Mobile

When AT&T handed Microsoft the keys to its 5G core network in 2021, it signalled that building next-generation wireless infrastructure is about choosing cloud platforms, virtualisation strategies, and spectrum portfolios – decisions that will determine which operators win in the next decade’s competitive markets.

America’s big three carriers deploy 5G using radically different technology stacks. AT&T is betting on Microsoft’s cloud, Verizon is virtualising everything in sight while owning its infrastructure, and T-Mobile is using mid-band spectrum it inherited from Sprint.

Each approach delivers measurably different network performance, and only one strategy can prove optimal as 5G matures toward 5G Advanced and eventually, 6G.

AT&T’s cloud-based 5G infrastructure: The Microsoft gamble

In June 2021, AT&T made an unprecedented move: it sold its internally developed cloud technology to Microsoft and committed to running its 5G core on Microsoft Azure. The deal transferred approximately 100 AT&T engineers to Microsoft, along with intellectual property developed over nearly a decade of building a carrier-grade cloud platform in-house.

The strategic calculation was stark. AT&T had spent years developing cloud-native network infrastructure but couldn’t match the scale and investment capacity of the hyperscalers. “The operator’s nearly decade-long cloud-native journey hit a crossroads,” as industry analysts noted when the deal was announced.

By October 2025, AT&T had launched its nationwide 5G standalone (SA) core built on Azure. The network now runs on what AT&T calls an “open, virtualised architecture” – more than 60 containerised network functions managing traffic for hundreds of millions of subscribers, all operating in a hybrid cloud environment that spans AT&T’s on-premises data centres and Microsoft’s public cloud.

The benefits are faster service deployment through software updates not hardware replacements, automated scaling during traffic spikes, and AI-driven network optimisation.

“Our industry needs to move away from calling it names and digits,” said Igal Elbaz, AT&T’s SVP of network cloud. “The architecture is different. It is cloud-native, like it or not. We are bringing AI into the wireless architecture, and it’s software-based. I want to be able to progress our network with a software push.”

The risk is that AT&T is now dependent on Microsoft for its most important infrastructure. If the hyperscaler partnership hits technical snags or pricing disputes, AT&T has limited alternatives. The company traded control for speed and scale – a calculation that public cloud economics beat telco-built infrastructure.

Verizon’s virtualisation infrastructure: Owning the stack

Verizon took the opposite path. Rather than outsourcing to hyperscalers, the carrier is building what it calls the “Intelligent Edge Network” – a virtualised infrastructure Verizon owns and operates end-to-end.

As of early 2025, Verizon has deployed over 22,900 virtualised RAN (vRAN) cell site locations with more than 170,000 Open RAN-capable radios in service in the country. These aren’t traditional hardware-based base stations, but software-defined radio systems running on standard hardware that Verizon can configure and upgrade remotely through software.

The technical achievement is substantial, with the company having virtualised its core network in containers. It virtualised baseband functions – the signal processing that traditionally required specialised hardware – letting the carrier run network functions on commercial off-the-shelf servers.

In February 2025, Verizon took virtualisation further by deploying a multi-vendor RAN Intelligent Controller (RIC) – integrating Samsung’s AI-powered Energy Saving Manager with Qualcomm’s RAN Automation Suite, marking an Open RAN milestone: different vendors’ equipment working together on standard interfaces, managed by AI software, not vendor platforms.

The advantage is control. Verizon isn’t dependent on Microsoft, Amazon, or Google for network functions, but can can optimise performance for specific needs, integrate with its fibre holdings, and avoid hyperscaler pricing issues.

The challenge is to build and maintain infrastructure, which requires technical expertise and ongoing investment. While AT&T can rely on Microsoft’s thousands of cloud engineers, Verizon staffs this internally.

As one analyst noted when AT&T announced its Microsoft deal: “mobile network operators, no matter how invested and talented in cloud computing, are no match for the might of hyperscalers.”

T-Mobile’s spectrum-driven 5G infrastructure: Efficiency over investment

T-Mobile’s strategy is different. It inherited a mid-band spectrum advantage from the Sprint merger and is it to outperform competitors on speed while maintaining lower infrastructure costs.

Opensignal’s January 2025 report showed T-Mobile delivering average download speeds of 158.5 Mbps – three times AT&T’s 53 Mbps and substantially faster than Verizon’s offerings. T-Mobile’s 5G download speeds reached 252.4 Mbps, compared to Verizon’s 169.5 Mbps and AT&T’s 167.8 Mbps.

T-Mobile achieved this performance advantage spending less on infrastructure than either competitor. The carrier’s CAPEX runs US$9-10 billion annually versus AT&T’s US$22-23 billion and Verizon’s US$17.5-18.5 billion.

Superior spectrum holdings from the Sprint acquisition and what CEO Mike Sievert calls “algorithmic” network deployment mean T-Mobile uses an AI model called “Customer Driven Coverage” that ranks tens of thousands of potential cell sites based on where customers need capacity rather than providing blanket geographic coverage.

“We’re not using blunt tools, like going in the countryside and building towers,” Sievert explained. “It’s much more algorithmic. The result is we will stay ahead of the demand curve and continue to extend our overall performance and 5G experience leadership in the CAPEX envelope.”

T-Mobile’s 5G standalone architecture includes network slicing abilities, letting the carrier partition network capacity for different services – enterprise applications, consumer broadband, IoT devices – each with their own performance characteristics.

The vulnerability is that if data consumption accelerates beyond mid-band spectrum capacity, T-Mobile will need extra infrastructure. It’s exploring millimetre-wave (mmWave) and multi-dwelling unit strategies as hedges, but admits it’s still “learning” whether these approaches can scale economically.

The performance divergence: What actually works

Independent network testing reveals how these different strategies translate to user experience:

Speed: T-Mobile dominates with 158.5 Mbps average (Opensignal), faster than competitors by 50-200%

Reliability: Verizon and T-Mobile tied with 898/1000 points (Opensignal)

Coverage: Verizon leads in overall coverage experience for the fourth consecutive report

Consistency: T-Mobile leads with 83.1% consistent quality experience

No single operator wins in all metrics. AT&T’s cloud-native core hasn’t yet translated to speed leadership, Verizon’s virtualised infrastructure delivers reliability but not velocity, and T-Mobile’s spectrum advantage provides speed but raises questions about long-term capacity.

What this means for 5G’s future

By 2028, as operators push toward 5G Advanced with more sophisticated network slicing, edge computing integration, and AI-native operations, architectural choices will vindicate or condemn strategic decisions made in 2021-2025.

For enterprises evaluating 5G services, the implications are that the operator with the fastest current speeds (T-Mobile) isn’t the one investing most in infrastructure. The operator with the most virtualised network (Verizon) doesn’t lead in absolute performance. And the operator outsourcing to hyperscalers (AT&T) is still working to translate cloud-native architecture into customer-facing benefits.

Only time – and user experience – will reveal which architecture choice was right.

(Photo by Boris Misevic)

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Tags: 5G, at&t, networks, t-mobile, telecoms, us, verizon