T-Mobile US and Verizon share a similar cloud strategy with clear lines drawn between what does and doesn’t belong on public clouds. 

Both carriers run core network functions and services on private clouds and plan to keep it that way for the foreseeable future. 

Public clouds will increasingly provide the necessary compute, storage, and additional capabilities for Verizon and T-Mobile’s efforts in mobile edge computing. Verizon is further along this path, as the only U.S. carrier with edge services slated to ride on all three of the world’s largest hyperscalers.

“The virtualization of telecommunications networks has been quite a complicated process,” Adam Koeppe, Verizon’s SVP of network technology and planning, said in a phone interview. 

Verizon Sticks With Internal Cloud Platform

“If you look at the directional technology for Verizon, all of it is being moved on to our virtual cloud platform. That's our internal cloud platform that we designed, created, administer, [and] operate for virtual network functions. That started with core network functions,” he explained.

As Verizon’s experience and capabilities in this virtual cloud environment grows, so too does the amount of functions running there. “As we look for the most sophisticated and efficient way to architect the network, you'll see a lot more virtual network functions running on our cloud platform,” Koeppe said. 

“On the 5G front, the entire 5G core that’s in development now will be on our cloud platform in a webscale architecture. 4G and 5G radio access nodes will have virtual basebands associated with most of them,” he added. 

Verizon’s internally deployed cloud platform services its network core, edge, and far edge — and all three have paths to virtualized infrastructure, according to Koeppe.

Each scenario requires a cloud platform, physical infrastructure, an operating system, and virtual or containerized network functions, he explained. 

AWS Outages Reinforce Public Cloud Hesitancy

Verizon and T-Mobile might be feeling especially justified in their approach to the cloud in the wake of two major Amazon Web Services (AWS) outages in the span of eight days. These outages served as yet another reminder that telecom networks can’t yet, and may never be able to, fully rely on public cloud infrastructure for critical services and workloads.

“Our cloud activity is more organic than inorganic on the network sector. So we have a lot of cloud infrastructure that we manage ourselves,” T-Mobile President of Technology Neville Ray said at Oppenheimer’s 5G Summit, according to a transcript. 

This includes T-Mobile’s 5G standalone (SA) core, which it deployed as the world’s first in August 2020 and remains the only 5G core operating in the U.S. today. 

While Ray described the cloud space as “massively transformative” in delivering efficiencies and other benefits, he’s thus far unwilling to hand T-Mobile’s most critical infrastructure and core services over to public clouds. 

T-Mobile Unwilling to Hand Over to Third Party

“The phone isn't going to ring, the data session is not going to happen unless that core service is up and running. I'm not at the point yet where I would put that in the hands of a third party,” he said. 

“I will use cloud technology and efficiency, but I will do that in-house,” Ray added. “We like to own that experience as much as we can ourselves because that's pretty critical in the nature of the business here.”

Koeppe advocates a similar set of cloud principles at Verizon. “It's a different landscape when you're carrying live voice, or data traffic, or video sessions, or 911 calls — all the things that run across our network on a daily basis,” he said. “Our focus, regardless of the type of architecture and infrastructure that's deployed, is to have the most reliable solution, the most reliable network on the planet." 

Throughout Verizon’s evolution from physical to virtual network functions, “reliability and security are still jobs one and two for the customer experience,” he said. “We apply such a tremendous level of diligence and rigor to ensuring the security and reliability of our networks. That’ll carry forward whether it's physical, virtual, open, whatever the case might be.”

A key driver of virtual network architecture rides on its ability to provide more sophisticated artificial intelligence and automation capabilities, which results in more reliability, according to Koeppe. But as with T-Mobile, Verizon prefers to keep the cloud platform running those critical services close and in house.

AT&T Charts Pure Public Cloud Path

Conversely, AT&T is going all in on the public cloud, effectively outsourcing its 5G core, network workloads, and services to Microsoft’s Azure for Operators platform. AT&T earlier this year sold its Network Cloud technology, engineering and lifecycle management software for containerized or virtualized network functions to Microsoft.

By shedding critical engineering talent, roughly 100 engineers, and moving the crown jewels of its network into Microsoft’s cloud, AT&T effectively decided to give up control of its internally developed network cloud technology. It’s also playing a lesser role in open source projects that were central to its previous vision. AT&T said it plans to move its existing network cloud to Azure by 2024.