Atrium 2016/A: ONF + ODL

ONF’s Kumar Jayaprakash and Saurav Das provide insight on the latest release of open source project Atrium.

The promise of SDN – “A fully interoperable multi-vendor network where infrastructure elements like SDN controller and switches from multiple vendors are able to communicate with each other seamlessly; the sheer choices and flexibility providing immense value and benefits to the end customer.”

We are one step closer to the promise of SDN and greater interoperability. Today, we have announced the availability of the second release of ONF’s open source project Atrium – an open SDN software distribution. The Atrium project delivers vertically integrated open SDN software distributions that make it easier for end users to build and customize the distributions to meet their unique requirements. Atrium 2016/A is the latest release of the distribution that extends into the OpenDaylight platform and builds on Atrium 2015/A, released last June. With its second release of Project Atrium, ONF takes one more step towards achieving better interoperability in the industry.

The initial release of Atrium 2015/A was the first distribution with a BGP peering router application developed for the ONOS controller, and it was designed to work across seven different OpenFlow switches. The Atrium 2015/A release also introduced the concept of “flow objectives,” a Northbound API and framework that allows applications to seamlessly work across different types of OpenFlow 1.3 data plane pipelines.

Atrium 2016/A, the second release of Atrium, ports the concept of flow objectives to achieve pipeline abstraction for SDN applications to the OpenDaylight Controller. The BGP peering application, which uses flow objectives, was developed on ODL by Wipro Technologies, as part of this release. Flow objectives are included as part of the Device Identification and Driver Management (DIDM) project in OpenDaylight and a new YANG model was developed by Criterion Networks for implementing the same.

The Atrium 2016/A release also brings in several enhancements for the ONOS-based router from the 2015/A release. We learned a lot from undergoing lab trials at AT&T, Bell Canada, and AARnet/CSIRO, and by performing interoperability demonstrations at the SDN Solution Showcases at ONS last June and the SDN & OpenFlow World Congress in Dusseldorf last October. With primary contributions from ON.Lab, we added support for static routes and untagged interfaces to the ONOS based router. We also improved the stability and scale of the router, by separating the BGP and OpenFlow traffic between the controller and switch, and took steps to ensure that data plane communication is not interrupted in the event of controller failure. Finally, we implemented Quagga’s FPM interface to ONOS, which allows us to potentially support an IGP (like OSPF or IS-IS) in addition to BGP in the Atrium router. This router is currently supported by EdgeCore and NoviFlow hardware OpenFlow 1.3 switches.

In the 2016/A release, we have also included a new vertically integrated solution for a data center leaf-spine fabric. This is the first time an L2/L3 Clos fabric has been built in open source, on bare-metal hardware, and with SDN principles. The Atrium fabric is designed to scale up to 16 racks, using well-established design principles of L3 down-to-the-ToR switch, where packets are L2 switched within a rack, and L3 routed across racks. The fabric is built on EdgeCore bare-metal hardware from the Open Compute Project (OCP), and switch software including OCP’s Open Network Linux, and Broadcom’s OF-DPA API. It leverages earlier work from the ONF’s SPRING-OPEN project that implemented segment routing using SDN. Primary contributors include ONF, ON.Lab, Broadcom, and EdgeCore. The fabric is set for a field trial with a major operator soon, as part of the Central Office Re-architected as Data Center (CORD) project with ON.Lab.

An interoperable implementation of the BGP peering router application that works across ONOS and ODL controllers was recently demonstrated at Open Tech India, an open networking SDN user event.

Phil Robb, Director of Networking Solutions, Linux Foundation, at the Atrium Demo

Flow Objectives are a key step forward in developing better interoperable applications. A reference implementation using an OVS two table pipeline for ONOS and OpenDaylight controllers is available for hardware vendors to leverage and develop drivers specific to their hardware architectures. Vendor specific drivers and more SDN applications that leverage flow objectives will be available as part of future Atrium distributions.

Interoperability is an evolving process. Standardization programs, interoperability events, and community projects like Atrium are important steps towards achieving SDN interoperability.

What’s next? Atrium 2016/B, the third release of Atrium slated for the second half of 2016, will focus on developing several new applications that address enterprise operator use cases. A complete demo of Atrium 2016/A will be available at the Layer123 NFV World Congress this April in San Jose.

Get involved. If you are a network operator, system integrator, independent software vendor, controller developer, switch vendor, SDN researcher, or freelancer, we are actively seeking your participation. Please send an e-mail with your name, company/affiliation, and your interest in Atrium to

To learn more about the Atrium project, visit the Atrium project page.

– Kumar Jayaprakash, Director of CNLabs & Vice Chair of Interop at ONF, and Saurav Das, ONF Principal Architect & Atrium Lead