The rate at which cloud-native network functions (CNF) are going to employed to drive next-generation networking services is about to accelerate following a decision by the Open Networking Automation Platform (ONAP) and Kubernetes working groups within The Linux Foundation to collaborate on a CNF architecture.
Arpit Joshipura, general manager for networking at The Linux Foundation, says that while telecommunications providers have been making extensive investments in network functions virtualization (NFV) software based on virtual machines, it’s become apparent to many that containers offer a lighter-weight approach to virtualizing network services.
It’s not likely CNFs will replace VNFs entirely, he says, but interest is accelerating rapidly because CNFs provide more portability and scalability than VNFs, which are optimized for one specific type of virtual machine platform. In fact, in many cases organizations are starting to load VNFs in Docker containers or deploy them on Kubernetes using technologies such as KubeVirt to make them more portable, Joshipura says.
Projects that will be impacted by aligning the efforts of the two working groups span efforts including LFN ONAP Multi-VIM, which enables ONAP to run on multiple platforms, and OPNFV, a framework for building NFV that supports a variety of container technologies including the Istio service mesh and Prometheus container monitoring software.
Additional work will involve the CNCF cross-cloud continuous integration (CI) framework, a Ligato tool for integrating virtual and physical networking, and a network services mesh to meld L2/L3 networking services on Kubernetes that borrows from concepts originally developed for the Istio service mesh.
For the most part, Joshipura says, The Linux Foundation expects Kubernetes to evolve into a management platform for managing and deploying CNFs that many carriers will deploy alongside their existing investments in open source OpenStack frameworks. For that reason, elements of the ONAP framework for managing network services already sits on top of Kubernetes, and the Casablanca release of ONAP expected later this year will complete the transition to a microservices-based architecture running atop Kubernetes. CNFs in some instances will be deployed on top of virtual machines, while in just as many other cases carriers may elect to deploy CNFs on bare-metal servers. That hybrid deployment model will be the common architecture for managing network services for the next decade or more, says Joshipura.
In general, carriers are migrating toward employing standard x86 platforms whenever and wherever possible to process network services versus relying on proprietary platforms. To facilitate that transition, physical appliances such as firewalls are being turned into CNFs and VNFs that can be deployed on an x86 server. The goal is to enable networks to scale to the point where they can support a wide range of 5G networking services that carriers currently are in the early stages of rolling out on x86 servers. Without a robust suite of CNF and VNFs in place that are centrally managed by a framework such as ONAP, however, it may take a while for most of those services to deployed at a truly global scale.