Op-Ed: AWS is winning the 5G cloud core race

• Microsoft made big moves in 2020 and 2021 to secure a pole position in the mobile core market
• But AWS has since gained momentum, inking core deals with multiple mobile operators
• There's one other thing that could become relevant down the line: AWS' liquid cooling capabilities

Far be it for me to declare winners and losers, but, well, I’m doing it.

Rumors have been swirling that Microsoft is looking to get out of the telco game and, more specifically, that it’s looking to sell the Metaswitch Networks and Affirmed Networks assets it acquired in 2020 to have a real go at the telecom market. But regardless of whether those rumors are true, one thing is clear from my vantage point: Microsoft is losing the battle for mobile core mindshare. And AWS is gleefully picking up the slack.

The current landscape is starkly different from where Microsoft sat just a few years ago in 2021. In June of that year, it inked a marquee deal to move AT&T’s 5G mobile core to its cloud platform. During its Investor Day event on Tuesday, AT&T reiterated its plans to go all-in on cloud core deployments, outlining plans to consolidate its mobility, IoT and enterprise cores to a “single public cloud provider.”

Strangely, though, it didn’t just say it was moving them to Microsoft Azure. Which is kind of odd when you consider that Microsoft built its Azure Operator Nexus platform using AT&T’s technology.

Despite the omission, an AT&T representitive told me that as far as the public cloud goes, "our plans remain unchanged." That is, AT&T is still deploying its "SA Core on Azure Operator Nexus in our data centers, on our hardware, operated by AT&T."

But it unavoidably feels like a burn that AT&T didn’t mention Azure given AT&T is the only operator listed as a customer on Microsoft’s Azure Operator Nexus website (For the record, it has zero customers displayed on its Azure Operator 5G Core site. In response to questions about how many operators run mobile core workloads on its cloud and its growth targets for the segment, Microsoft told Fierce that telecom remains a "priority industry" for the company but otherwise didn't answer the questions.). In contrast, AWS has at least three operator testimonials front and center on its AWS for Telecom page.

For anyone looking, signs of trouble for Microsoft were already creeping out of the woodwork in the months leading up to its AT&T announcement. Dish Network, which at the time was beginning work to buildout a greenfield 5G network across the U.S., chose Amazon Web Services (AWS) as its cloud partner.

In 2023, Hawaii-based mobile carrier Mobi launched an MVNO on T-Mobile’s network using a mobile core running on AWS. And things only continued to pick up steam in 2024.

Japan’s NTT DOCOMO led the charge in February announcing plans to use AWS to deploy its open RAN network and 5G core. Amazon said at the time the deal marked “the first-time a telecom operator is migrating its existing network and customers to a new 5G cloud network running on AWS.”

Soon after, Europe’s O2 Telefonica made the leap to AWS and U.S. cable giant Comcast (which operates a hybrid MVNO network) followed suit this week.

AWS didn't immediately respond to a request for comment about the total number of operators running their mobile cores on its cloud and its growth targets - likely because everyone and their mother is busy at re:Invent this week. But I'll update this piece if I hear back. 

The cool factor

I’m self-aware enough to know that it’s hardly groundbreaking to say a multi-billion-dollar company is winning at something, much less something where there are really only two other viable competitors. (Google Cloud, for the record, does have a telecom business. But that one trial deal with Deutsche Telekom aside, it seems to be much less focused on mobile core deployments and more on using the cloud to improve things like cybersecurity, customer service and generative AI for telecom customers.)

But I do think there’s one unappreciated factor in the mix that – while not necessarily a deciding factor today – could become key in the future: liquid cooling.

Though it has caught on like wildfire in the data center arena, liquid cooling has gotten something of a chilly reception from telecom providers. That’s because until now, telcos haven’t had a reason to care.

Nokia and Iceotope both offer liquid cooling options for mobile base station equipment, but despite some sporadic trials with the likes of Elisa and AT&T, not much seems to have come of these product announcements. And that…kind of makes sense.

I get why Nokia and Iceotope went after the RAN given it accounts for upwards of 80% of energy used by a network. But to paraphrase what Ericsson told me in an email when I asked them about this: why would you use liquid cooling – which is more complicated, requires power and has the potential to seriously damage expensive gear – when passive cooling techniques more than do the job?

Telcos by and large seem to agree with that stance on liquid cooling in the RAN. But there’s one place where traditional cooling won’t be able to cut it for much longer: the cloud.

It’s true, as Dell’Oro Group Data Center Physical Infrastructure guru Lucas Beran has told me repeatedly, that not all servers will require liquid cooling. But I’d bet that as more mobile core workloads move to the cloud and as AI infiltrates deeper into the network that such workloads could cross the threshold and require performance beyond what air-cooled chips are capable of. And we’re not even talking about what 6G will require yet.

Operating under that assumption, then liquid cooling capabilities will become a differentiating factor (assuming, of course, AWS doesn’t end up the only real game in town) and a potentially huge cost saver.

And what do you know, AWS just announced a new slate of data center components that make it possible to retrofit its existing equipment with liquid cooling tech.

Yes, Microsoft and Google Cloud are also working to incorporate liquid cooling solutions in their data centers. But when you zoom back out and see which cloud provider offers all the puzzle pieces – a robust telecom business, proven partnerships, momentum, cooling capabilities and scale – AWS seems to come out on top.

At least for now.