The trend to virtualize telecoms networks – running them as virtual network functions (VNFs) in software, on off-the-shelf hardware – was once driven almost single-handedly by standards body ETSI. The organization’s Network Functions Virtualization (NFV) specifications were the basis of early work on software-based telecoms systems, and remains their bedrock.
However, NFV progress stalled as the industry’s efforts fragmented at higher layers, notably with the stand-off between separate ETSI and Linux Foundation efforts to set standards for management and orchestration (MANO). In addition, early deployments were seen as expensive and cumbersome, and many operators now want to wait until more modern technology – cloud-native systems built on containers, to replace first generation virtual machines – is mature, in order to improve the returns they expect.
So ETSI’s latest NFV moves are important, because they show the body upping its game after a period on the defensive, by integrating 5G far more tightly into virtualization. This makes sense now – very few mobile operators, contrary to expectations when NFV was first released, are embarking on major standards-based virtualization roll-outs in 4G. There are proprietary systems, especially in China; some virtualized 4G cores in operation, though mainly for smaller-scale or greenfield applications; a couple of MNOs planning cloud-native 4G, notably Rakuten.
However, for most, large-scale virtualization of key network elements will come with 5G – and often, especially in the case of the vRAN, only in a second phase of 5G build-out, when the business case demands that the operator makes the complex migration to the 5G core, and to a significantly different RAN platform, which can support all the 5G capabilities including those for Industrial IoT, rather than just faster broadband.
So ETSI has been working more closely with 3GPP to ensure that its new NFV updates have more intrinsic 5G support in areas like resource management, orchestration and network slicing within a dynamic, virtualized mobile environment. Its NFV Industry Specifications Group (ISG) has been collaborating with 3GPP’s SA5 Working Group on the network and application management aspects of NFV, so that the 3GPP-defined management system interacts with ETSI NFV MANO.
The first two of the new updates are being layered on top of ETSI’s NFV Release 2 specification, first published in 2016. They will ensure interoperability between a 3GPP-defined management system and ETSI’s NFV MANO system. This will support resource management for virtualized core networks, virtualized RAN and network slicing. They will join a release that was focused more broadly on management of virtualized resources; lifecycle management of network services and VNFs; performance management; and virtualized resource capacity management. At the time, there was no mention of 5G, since those standards were too immature to be fully integrated.
More recently, ETSI added the first specs within Release 3, which does include specific 5G focus. This added support for network slicing in NFV, management over multi-administrative domains, and multi-site network connectivity. “These features are essential to address the variety of applications expected to run on top of a 5G system, whether using distributed resources over multiple sites, centralized or a combination of both,” ETSI said. These features will not, however, be ‘backported’ to Release 2.
In addition, NFV network slicing was defined as a composite element of the 3GPP SA5 network slice subnet architecture, which will make it easier to deploy the 3GPP SA5 Network Resource Model and the ETSI NFV Information Model together.
Stage 2 specifications for Release 3 will be finished this summer, with stage 3 specs following later in the year, and the group has already begun work on Release 4.
This will concentrate on enhancing NFV infrastructure (NFVi) to support lightweight virtualization technologies such as containers, addressing one of the main accusations against NFV, that it is behind the times when it comes to modern cloud-native architectures. Other areas of focus in Release 4 include enhanced NFV automation, lifecycle MANO, an updated NFV MANO framework, and simplification of NFV deployments.
“As a founding partner in 3GPP, ETSI has a major role to play in contributing and aligning specifications and requirements,” said Cristina Badulescu, ETSI ISG NFV’s vice chair.