Despite significant industry investment, Network Function Virtualisation (NFV) appears to have progressed quite slowly since the first concept paper published in 2012. At the same time, operators have been understandably a little cautious about transferring the very heart of their businesses from purpose-built tried-and-trusted telecoms systems to a software-centric architecture built on off-the-shelf IT hardware. The adoption of NFV also brings with it a cultural change as operators effectively become software companies.

In the world of NFV, the standards required to tie the many moving parts of a mobile network together are still evolving. One of the fundamental benefits proclaimed for virtualisation was that it would reduce operators’ reliance on a single vendor: of course, the emergence of new, possibly unfamiliar, virtual network function (VNF) suppliers also means operators are faced with far more choices to make. What’s more, they also need to ensure that all these different VNFs are seamlessly interoperable with each other and with their selected NFV Infrastructure (NFVI), Management and Network Orchestration (MANO) systems.

Operators also have choices in terms of transformation strategy. Do they switch the core network to NFV and then move out towards the radio access network, or adopt a strategy of deploying all new network functions on NFV?

To help operators and other players in the mobile industry ecosystem better understand these issues, Mobileum recently took part in the Open Multi-Vendor NFV Showcase. Participation in this ETSI initiative enabled us to test the compliance of our VNFs with the latest versions of the evolving specifications and to check interoperability of our NFV-ready network functions with other VNF, MANO and NFVI providers.

The findings from the showcase demonstrations – which successfully proved the viability of a multi-vendor eco-system used to deploy an evolved packet core – were presented to the Open Infrastructure Summit in Denver at the end of April.

Our contribution to the showcase included a virtualised Smart Diameter Routing Agent (vSDRA) and a virtualised Network Traffic Redirection (vNTR). These functions proactively contact outbound roamers and steer them to the most appropriate visiting network.

At the showcase we were able to prove that our vSDRA module could receive LTE Diameter Signalling messages from a virtualised Mobility Management Entity (vMME) deployed on a virtualised Enhanced Packet Core (vEPC) all using open source software from the Open AirInterface Software Alliance.

The vSDRA messages were then routed through our vNTR module to register the roaming subscriber to a vHLR provided by ng4T. Management and orchestration was based on a commercial distribution of Open Source MANO (OSM) provided by Whitestack. For the demonstration, virtual machines created on Intel hardware hosted all the VNFs.

The showcase successfully demonstrated all the capabilities and proved that multi-vendor functionality was achievable – but it also showed that while there has been good progress on standardization, some of the standards needs extra detailing to avoid unwanted surprises when functions from different vendors are integrated.

Mobileum will continue to be at the heart of that work because as the industry moves to 5G, all network functions will have to be NFV-ready and truly cloud native to make the most of the new business and service opportunities that can be delivered through concepts such as network slicing.