Virtualized radio access networks (vRAN) and open RAN are oftentimes used interchangeably, but there are important, technical differences between the two RAN frameworks. 

Virtualization, which largely got underway in telecom networks during the scale-up period of 4G LTE, originally made its mark in the network core and has since pushed further out to the edge of networks in RAN. vRAN architecture is an evolution of RAN that employs NFV to automate network functions via cloud-based software and common-off-the-shelf servers.

Open RAN is a blueprint or series of specs being defined by organizations like the O-RAN Alliance, the Telecom Infra Project (TIP), and the Open Networking Foundation (ONF). It also enjoys broad support from lobbying groups like the Open RAN Policy Coalition, and regional operator-led coalitions in Japan, Europe, and elsewhere. 

Open RAN, or the O-RAN spec as defined by the O-RAN Alliance, is framed as an alternative to the proprietary nature of RAN and the effective monopoly enjoyed by a small group of global RAN suppliers. Open RAN calls for a complete disaggregation of network hardware and software with open interfaces that allow third-party software and white-box hardware vendors to earn a spot in a broader and flat architecture.

Rakuten Mobile, which currently operates the only fully open RAN network in the world, runs on various commoditized hardware surrounded by a moat of software from at least 10 vendors. Dish Network, which intends to deploy a nationwide open RAN 5G network in the U.S., has inked contracts with dozens of vendors for its planned network. 

Open RAN is a nascent and exceptional framework, particularly at mass scale, but a growing number of global operators are throwing their weight and money at open RAN for its ability to loosen the grip incumbent RAN suppliers have on the industry. 

However, because vRAN and open RAN are still so often used in a reciprocal fashion, SDxCentral asked a few industry executives to describe the important differences, if any, and what defines vRAN and open RAN from their perspective.

Cisco Views Open RAN, vRAN Synonymously

“I gave up trying to define the difference to anybody except for technologists,” Jonathan Davidson, SVP and GM at Cisco’s Mass-Scale Infrastructure Group, said. From an end-user perspective, vRAN and open RAN are synonymous although there are technical differences, he added. 

“The goal and the outcome are the same. We want to create an open ecosystem with open interfaces that are able to be used by multiple vendors with the outcome of lowering costs, and driving a just much faster pace of innovation,” Davidson said, adding that open RAN now enjoys broad support.

“The vRAN portion was kind of a step there. We also have been driving an open ecosystem around open vRAN, just because a lot of things were virtualized to start, but everyone is now moving to a cloud-native architecture” with O-RAN compliant interfaces, he explained.

Part of the overlap is also due to timing, according to Davidson. “When some of these companies started, open RAN didn't exist, and there wasn't a formal definition of what those APIs needed to look like,” he said. “But everyone now is moving to open RAN, so it's less of a concern than it was even a year or 18 months ago.”

Intel Details Differences, Highlights Trends

Dan Rodriguez, VP and GM of the Network Platforms Group at Intel, broke down the differences between vRAN and open RAN in a rather succinct fashion. “vRAN is a category, a type of RAN if you will, so it is a radio access network that’s built on virtualized network servers,” he said. “It allows you to have the scale agility in the radio access network utilizing cloud technologies.”

Open RAN, which can also be used in conjunction with vRAN, is “really a specification or a spec on how you have interoperability across multiple RAN components, so the radio and the base station,” he said.

Intel VP Asha Keddy, during a virtual summit hosted by Chetan Sharma Consulting, said the trends of network virtualization, automation, and broader interoperability are all fueling the rise of vRAN and open RAN.

In previous network infrastructure architecture, operators had to dispatch tower climbers to push out a new service. Virtualization removes that expensive and time-consuming task and providers operators with the flexibility to go “from custom to general purpose networks” that can be augmented with different components or services more quickly, Keddy explained.

“Cost and flexibility is where Intel sees this as a big need,” she said, adding that operators and vendors are inevitably seeking out flexibility and lower costs wherever possible. “I look at this as the virtualization journey, and there’s some benefits to it, including the open source community on the software side that generates innovation.”

VMware: Open RAN is Evolution of vRAN

According to Lakshmi Mandyam, VP of telco and edge cloud product management at VMware, a company with legacy in network virtualization (it’s effectively in its name), open RAN is an evolution of vRAN. But it’s all part of the desire among operators to move away from siloed stacks and single, entrenched vendors, she said. 

Virtualization of the RAN is the first step, similar to what occurred in the wireless network cores, because it provides operators with the flexibility to deploy and deliver new services quickly. The RAN space is going through an evolutionary and phased transformation similar to what occurred in internet network infrastructure, Mandyam explained.

“Now, some people may choose to go directly to open RAN, but I think a lot of the operators are cautious,” she said. “They want to undertake a kind of stepwise evolutionary journey.”

The key, Davidson said, “is we all want to get to open RAN.”