The Open Networking Foundation (ONF) today released SD-RAN v1.0, a cloud-native open radio access network (RAN) project it revealed last summer.

ONF is targeting the RAN for the first time to address what it considers inadequacies in other open RAN projects, including those being led by the O-RAN Alliance. The group is consuming architecture and specifications designed by the O-RAN Alliance, but specifically removing hurdles that third-party "xApp" developers confront when working with the near real-time RAN Intelligent Controller (nRT-RIC). xApps are designed to control the RAN and house the most important functions required to give operators more administrative RAN sovereignty over functions that are typically implemented as proprietary features on base station equipment. 

“This goal is achieved with an xApp SDK, the beginnings of which were part of the first release,” explained Saurav Das, VP of engineering at ONF. The group intends to continue improving upon that SDK and provide xApps more portability across different nRT-RIC platforms, Das added. 

This SDK stands among a series of features that set ONF’s SD-RAN project apart from open RAN activities underway in other open source communities, he wrote in response to questions. ONF is also developing extensions to O-RAN interfaces for different RAN use cases that it plans to contribute to the O-RAN Alliance for broader standardization. 

“We have a decade of experience building scalable, high performance, highly available SDN controllers, and our open solutions are now in production with multiple operators,” Das wrote. “We are leveraging this experience, expertise, and codebase for our nRT-RIC implementation, and this makes the SD-RAN approach unique.”

SD-RAN v1.0 is a developer release in the “incubation phase” and is only currently available to ONF members, including Aarna Networks, Airhop Communications, AT&T, China Mobile, China Unicom, Cohere Technologies, Deutsche Telekom, Facebook, Google, Intel, NTT, Parallel Wireless, Radisys, and Sercomm. 

The first version of SD-RAN includes ONF’s µONOS-RIC, the foundation’s nRT-RIC that interacts with distributed and centralized RAN units via O-RAN interfaces, encodings, transport protocols, and service models. ONF also describes SD-RAN as an “integral part” of its Aether edge cloud platform that was first released in March 2020, and was recently tapped as the software layer for a $30 million project funded by the Defense Advanced Research Projects Agency (DARPA).

Das said a lab is being established in Berlin with support from Deutsche Telekom and the Telecom Infra Project to focus on nRT-RIC compatibility and multi-vendor interoperability. ONF also expects SD-RAN member operators to begin trials later this year.

SD-RAN will see updates through releases each quarter, and the next few releases are expected to include new use cases, service models for physical cell identifiers, mobile handovers, and capacity and coverage optimization, according to Das.