What’s up with AT&T and its multi-vendor open RAN strategy?

  • AT&T insists it’s taking a multi-vendor approach to open RAN  
  • Ericsson was slower to the open RAN party than a lot of other vendors, but now it’s in the driver’s seat at AT&T
  • How many vendors will be in the back of the bus?

There’s been a lot of hoopla around AT&T’s open Radio Access Network (RAN) strategy. Is it a single-vendor approach or, as AT&T insists, a multi-vendor strategy?

At TM Forum’s DTW: Ignite event in Copenhagen last month, AT&T executives made a point of saying they’re moving to a multi-vendor environment as part of last year’s $14 billion, five-year contract with Ericsson.

But so far, it sure looks like a whole lot of Ericsson.

How long does AT&T expect this path to a multi-vendor environment will take? Fierce caught up with Maulik Shah, who works in the AT&T Radio Access Network engineering headquarters, to get some answers. Shah reports to Todd Zeiler, VP of Wireless Engineering at AT&T.

When AT&T awarded that blockbuster contract to Ericsson late last year, the planning process of ripping out Nokia hardware and replacing it with Ericsson got underway. That meant a lot of logistics in December and January, including leasing, zoning and real estate transactions before the actual physical work of swapping out the Nokia hardware.

Since then, quite a few markets are being swapped out, including sites in New York, New Jersey and Pennsylvania in the Northeast, as well as Ohio and Arizona, Shah said. The process continues on a site-by-site basis.

Right now, AT&T is sourcing the new radio hardware from Ericsson. Fujitsu’s open RAN radios have not yet been certified to work on AT&T’s network, according to Shah, but the expectation is that Fujitsu, Mavenir and anyone else who qualifies will get a crack at it.

“We’re working with multiple other radio vendors to see if they have what meets our requirements so that we can add to our portfolio. That’s the beauty of what we are getting into with this open platform – is that we would be able to mix and match,” he said.

Of course, it’s not just about the radio units, or RUs. During a well-attended panel session at Connect (X) in May, Zeiler talked about the pivot away from "cell sites" to a world where it’s all about the CU, DU and RU.

Since Zeiler was out of pocket at the time of our interview, we asked Shah to elaborate on that.

As the industry evolves to virtualization, the competencies within the RAN shift to three buckets. The radios are one aspect, and that’s where a lot of innovation is happening. From there, the components in the baseband are disaggregating into two distinct pieces: the distributed unit (DU) and the centralized unit (CU).

Each operator may handle it differently, but AT&T is putting the DUs at the bottom of the 5G sites and the CU at a central location where “we would be able to pool the resources over there,” Shah said. “As we think about cell sites, it’s getting much more disaggregated into these components.”

While Ericsson currently supplies the RUs, it’s also driving the DUs and CUs. Servers are coming from Dell. But much of the industry is focused on the RUs – that’s where Zeiler said most of the disruption is expected to occur.

How quickly will AT&T have another vendor certified to supply radios? Again, “we are actively working with multiple vendors,” Shah said, suggesting it’s not imminent, but surely by this time next year, everyone will have a much better idea of who’s included in this multi-vendor strategy.

What analysts say   

Earl Lum, founder and president of EJL Wireless Research, said that because Ericsson is the primary vendor, any secondary vendor for Massive MIMO radios at AT&T will need to develop configurations that are compliant with Ericsson’s.   

“There’s no way any startup’s ever going to be the primary vendor on the radio side or even on the DU side” because they don’t have the deep pockets to provide things like a lifetime warranty, he said.

The pressure is on any new radio vendor to work seamlessly with Ericsson, he said.

“If you’re the systems integrator, you’re driving the bus. Just like Ericsson is driving the bus. Why do you want to sit in the back of the bus when you could be driving it? Driving it means that if somebody is yelling at the back of the bus, you just tell them to shut up,” Lum quipped.

The ability to have many vendors supplying product is most important for the RU because it’s the most expensive, according to Recon Analytics analyst Daryl Schoolar. And he doesn’t rule out Nokia as a future radio supplier to AT&T either.

“The door’s not closed on Nokia. It could still supply radios,” he said. Samsung and Fujitsu also come to mind as potential Massive MIMO radio vendors on top of Ericsson’s DU and CU, with vendors like Mavenir potentially in the picture.

Vendor enthusiasm

Naturally, AT&T’s emphasis last month on a “multi-vendor” network strategy sparked a good deal of enthusiasm from vendors hopeful of getting a piece of AT&T’s open RAN business.

Mavenir, Samsung and antenna supplier MatSing were among those who provided statements to Fierce about the promising direction of open RAN and AT&T’s desire for open, interoperable and disaggregated networks. AT&T’s open RAN plan is for 70% of its wireless network traffic to flow across open-capable platforms by late 2026.

Mavenir said it’s “excited by the opportunity this presents to Mavenir and the wider ecosystem of O-RAN Alliance compliant vendors.”

Samsung said it already has proven experience supporting brownfield and greenfield open RAN deployments using Samsung vRAN architecture with its own radios and third-party radios.

“Not speaking on carrier-specific initiatives here, but, as an industry we are progressing toward an ‘open network’ where performance, deployment and cost are all enhanced by the O-RAN architecture,” MatSing CEO Bo Larsson said in a statement. “Time is of essence as large-scale transitions take time – even years! Standalone architecture, network slicing, 5G-Advanced and O-RAN, alongside mid-band spectrum utilization, are all technologies that we are looking forward to that will propel the network capabilities and performance of the carriers further."

Single vs. multi-vendor

Part of AT&T’s efforts to expand the vendor ecosystem involve the Acceleration of Compatibility and Commercialization for Open RAN Deployments Consortium (ACCoRD, a program supported by $42 million from the National Telecommunications and Information Administration (NTIA).

AT&T and Verizon are leading the project, with participation from Japan’s NTT DoCoMo, India’s Reliance Jio and academic institutions. Suppliers for ACCoRD include Microsoft, Nokia, Radisys, Airspan, Ericsson, Fujitsu, Rakuten, Samsung, Mavenir, VMWare, RedHat, Wind River, Ciena, Cisco, Dell, Intel, Amdocs, Keysight and Viavi.

But managing multiple vendors isn’t easy. Just look at EchoStar/Dish Network, which is struggling financially but holds the title as the first with a cloud-based, open RAN network in the U.S. Dish didn’t expect to take on the role of systems integrator but ultimately did. It remains its own systems integrator to this day, a spokesperson confirmed to Fierce.

“When you’ve got a lot of vendors, you’re herding a bunch of crazy cats. It takes a lot of energy to herd them all into the same line and have them marching together,” Lum commented. “That’s why Dish had all these crazy problems and it was a large learning curve.”  

That loops back to the age-old question: What are the benefits of multiple vendors? Some would argue it’s easier for an operator to work with fewer vendors for the sake of simplicity – the old “one throat to choke” saying.

With a multi-vendor approach, “it gives us the ability to pick the right vendors that are suited for what we want to do with our network,” Shah said.

As for who’s going to act as systems integrator: “Right now, we are going through the process of understanding how the integration would work and figuring that out, so more to come on the systems integration piece,” he said. “I wouldn’t rule anybody out or in right now.”