vRAN performance a match for legacy approach, Verizon VP says

There has been ongoing industry debate as to whether vRAN can match the performance of traditional networks, and Bill Stone, Verizon’s VP of Technology Development and Planning, shared which side he lands on.  

“I stand extremely firmly on the side in that we would not be deploying it if it wasn’t as good or better than what we have in place today,” Stone said in an interview with FierceWireless. 

Verizon was the first U.S. carrier to implement commercial vRAN gear from Samsung as part of an expansion of the carrier's 5G Nationwide service in December. Samsung is supplying applications software for the vRAN network functions, or baseband - virtualized distributed unit (vDU) and central unit (vCU) - functions that can run on general purpose hardware. Other vendors named as Verizon vRAN partners include Intel, HPE, and Wind River.

Verizon has been putting vendors through their paces, Stone said, with extensive testing, including well before the recent launches, which used Samsung in markets in upstate New York and New England.

“We held the vendors’ feet to the fire, like we always do, and absolutely it’s performing every bit as well as the legacy, custom-based approach,” Stone said.

Historically in the radio access network (RAN), operators, including Verizon, have been dependent on hardware and software supplied by the same vendor. With vRAN software from different vendors could run on the same common hardware. One of the drivers Stone cited for Verizon pursuing RAN virtualization is more flexibility.

RELATED: Verizon deploys Samsung vRAN in 5G expansion

“By decoupling the hardware from the software we create a much more flexible network environment, that becomes much more conducive, toward automation, orchestration,” Stone said. “And then just the flexibility in general as you become more software oriented, the ability to scale up different parts of the network, scale out different parts of the network.”

That means moving network functions out toward the customer as needed, or adding capacity where different network functions sit at the edge.

“Being able to do that on common hardware in a much more software-oriented environment is certainly the direction we want to go in,” Stone noted.

Still, with a way new of doing things and shift from legacy physical network functions to software environment comes a learning curve, including training to become familiar with automation and orchestration capabilities.

“As we soon as we get up the learning curve and our technicians become skilled at orchestration we start to benefit from it right away,” he said.  

Wind River just this week debuted a cloud-native infrastructure software and analytics platform. Its Kubernetes and container-based architecture is used by Verizon to help deploy and mange distributed edge networks. It also offers core-to-edge orchestration.

Aligning with Verizon’s network vision

Aside from the inherent benefits of scaling more efficiently and effectively, creating a flexible network via virtualization aligns with Verizon’s longer-term network plans including mobile edge compute.

Verizon sees its use of high-band millimeter wave spectrum for 5G Ultra Wideband service as a differentiator, especially combined with MEC. It already launched 10 mobile edge compute (MEC) zones in partnership with AWS, and wants to use its 5G network for MEC in private wireless or on-site networks. 

“This type of flexible network architecture plays right into the MEC approach,” Stone said.

RELATED: Verizon’s Vestberg makes private vs. public 5G MEC distinction

With a more distributed software-based architecture and network functions closer to the edge, virtualization means Verizon can implement future capabilities (like MEC platforms) much more easily in locations that sit closer to the customer – which at the same time lets Verizon’ deliver the lower-latency promise of edge compute.

“And you can push that concept all the way down into say a venue location or even a specific customer location,” Stone noted. 

Verizon has 5G partnerships with a variety of sports and entertainment venues, like delivering 5G Ultra Wideband to NFL stadiums. It also has vendor partnerships with Microsoft and others for enterprise private wireless networks.

Open RAN in parallel

As Verizon continues to virtualize, it’s also pursuing open RAN hand-in-hand.

They are technically two different paths, Stone noted, but there is overlap.  Part of that is vRAN provides flexibility terms of deploying scale and managing the network, while O-RAN gives more flexibility in combining different vendors. 

RELATED: AT&T moves forward on open RAN while T-Mobile takes cautious approach: Special Report

“As we move into virtualizing the RAN it makes a lot of sense to push forward with open RAN or O-RAN, compliance with the O-RAN specifications, at the same time,” Stone said, adding efforts on the two aren’t necessarily in sync, with each a bit further ahead than the other in different regards. “It is our desire to combine both of them as much as we can.”

More locations, more integration

Verizon’s virtualization work in its RAN is part of a larger multi-year network redesign and follows earlier focus on virtualizing the core.

And Stone views RAN virtualization as a natural extension.

One difference he cited in dealing with the RAN is that it's much more distributed. In terms of challenges in implementing virtualized RAN versus the core, Stone acknowledged the increased number of locations that need to be both managed and touched because of moving closer to the edge. That compares to the core, which relies on fewer locations filled with the so-called “racks” for compute.

“It’s mostly a natural extension, but as you move away form the core and closer and closer to the edge, the number of locations does increase dramatically” Stone said.

Part of the overall virtualization strategy is also the ability to work with and more easily introduce a diverse set of vendors. It puts the carrier in a position, he said, to take advantage of innovative suppliers to deliver the complete network function solution. In a traditional network architecture, one vendor may own all of the components or portions, but it requires a lot of R&D and that single supplier may not be great at all of them.

“With this more flexible approach we can have competition at each layer of the stack and put together the best-in-class stack across multiple vendors” be it the supplier with the most experience or the greatest capability in that particular area. It’s part of the longer-term benefits Stone said the carrier expects to reap as Verizon pushes on with RAN virtualization in moving along the innovation path more quickly. There's also the opportunity for better pricing, but Stone said he tends to view it through a lens directed on innovation. 

Ed Gubbins, principal analyst at Global Data, echoed similar sentiment earlier to Fierce about vRAN and if more deployments follow Verizon's, potentially enabling "a new breed of competitors" and giving "operators like Verizon more choices and perhaps more pricing power when they select their RAN vendors." 

That said, when working with multiple vendors across an increased number of locations for virtualized RAN, integration and management of various network elements becomes a consideration.

This kind of integration work is "probably the biggest challenge with virtualization approach overall,” Stone said, adding extensive testing happens before anything is deployed in Verizon's commercial network. 

RELATED: NTIA explores open 5G stack competition to support DoD missions

Right now Verizon plays a big role and is taking on most of that integration, according to Stone, working hand-in-hand with vendors to integrate the different layers. But in general it’s is something the carrier also wants the vendor community to step up its own game in.

“That is something we’ll be looking to opportunities to explore other options to facilitate integration testing,” Stone said, including possibly having a vendor take on that responsibility in the future.

This isn’t to say Verizon isn’t sticking with its traditional vendors as well. Typically the bigger names are supplying network function application software when it comes to virtualization. In Verizon’s virtualized core for example, the usual suspects are at play including Ericsson, Nokia, Cisco and Oracle. Verizon is also using Intel, HPE and Red Hat. 

“It’s a mix of vendors between potentially smaller and traditional very large vendors that are supplying different parts of the ‘network stack’,” Stone said.