AT&T made a lot of hay out of its six-year push to virtualize 75% of its network functions, a goal it claims it reached in September 2020. The operator earned a lot of praise for being so outspoken about the effort earlier than its competitors, but something changed in the last few months, and signs suggest AT&T has relinquished its leadership role, according to LightCounting.

Key executive departures, including that of former AT&T Communications CEO John Donovan in summer 2019 followed by Chris Rice, the operator’s former SVP of network cloud and infrastructure, the following summer appear to have precipitated a shift in strategy, the analysts conclude.

“If any one operator has sort of driven the whole vision of disaggregated, that software-defined networking, virtualization, white boxes, this is something that AT&T has pushed more than any other operator, and they put it into effect as well,” Roy Rubenstein, consultant at LightCounting, told SDxCentral in a phone interview.

“Its contributions, the various open source projects they then contributed to these open source organizations has been significant,” he said, adding that AT&T was, at least until late last year, “a real trailblazer.”

Grant Lenahan, partner and principal analyst at Appledore Research, has a less complimentary view of AT&T’s stature and success on virtualization. “It’s not clear how far ahead AT&T ever were,” he wrote in response to questions.

The operator hasn’t suddenly reversed course or changed its focus on network transformation, but there’s been a noticeable decline in proclamations around this effort by AT&T brass and multiple direct and indirect factors are likely playing a role in that softening, Rubenstein said. AT&T might have determined that trailblazer status didn’t serve the company well or it could simply be a shift in priorities, he added. 

“There’s definitely been a change in terms of AT&T’s own vocality and in a sense the industry has lost an important evangelist of this,” Rubenstein said. 

AT&T’s more muted approach to these efforts could be the result of a less aggressive strategy, but he notes that “it’s very hard for one company to sustain this indefinitely, and also, one company can’t do it on its own.”

AT&T would certainly dispute any characterization of its virtualization efforts as less fortright or impactful. CTO Andre Feutsch and other technical leaders at the company consistently frame AT&T's network story around its broad vision to have a more software-centric network aided by the rise of open source hardware and software.

Rubenstein's view isn't so much that AT&T has reversed course, but rather that the company is making less of a concerted push on its own and facilitating more of its network transformation efforts through larger communities. Perhaps AT&T's recently increased investment and involvement in the Cloud Native Computing Foundation (CNCF) is one example of that shift.

More broadly, AT&T and other top 10 global operators have collectively transitioned to what LightCounting calls the second phase of network transformation, which involves the development and deployment of 5G, cloud-native functions (CNFs), edge computing, open networking, partnerships with cloud and internet providers, and new services.

While AT&T’s 75% milestone suggests it still has another 25% to go, that math doesn’t really add up, according to Rubenstein. The operator has effectively virtualized everything it intends to operate with software in the core of its network and the remaining 25% represents network functions or services that will just be operated to the end of their life and then decommissioned, he said.

AT&T’s decision to frame its virtualization journey on a percentage basis was also an over simplification of the work involved and objectives it achieved, Lenahan explained, adding that most operators use this framework to make their results appear more flattering.

“It’s very unclear and early announcements were unlikely or unrealistic,” he added “Solid, well understood metrics would be really useful” to gain a better understanding of what exactly has been virtualized.

The biggest bottleneck on virtualization is the service life of equipment, and that’s why Appledore Research believes the virtualization journey will span roughly two decades throughout the industry, according to Lenahan. “It’s also worth pointing out that the entire idea of virtualization flies in the face of decades of [99.999% reliability] thinking and deep, precise control of all assets, and therefore is a cultural shift,” he said.

Appledore predicts that AT&T’s virtualization effort will be complete around 2030, with more than 90% of that achieved by 2027.

Will Townsend, senior analyst at Moor Insights & Strategy, still views AT&T as the virtualization leader among its peers in the U.S. and he expects the operator to achieve complete network virtualization within the next three years.

Meanwhile, AT&T’s focus has moved to the edge, disaggregated cell site gateways, IP routing and core routing software, white box routers, open radio access network (RAN) development, and AT&T’s network cloud, according to Rubenstein.

This second phase of network transformation, or cloudification, is a continuation of early SDN efforts but also more interesting and complicated initiatives that start to complete the story, he added.

“5G is the key catalyst. … 5G is the point where cloud-native network functions come in,” alongside virtualized RAN and open RAN. Whereas, the first stage was fueled by the use of NFV to virtualize the network core, enterprise applications, and virtual customer premise equipment, he said. 

5G “can be viewed as bringing virtualization and the cloud to the edge, and then you’ve got a much more sophisticated network, but it’s a more complex problem,” Rubenstein said.