5 Challenges for NFV in the 4G Core Network5 Challenges for NFV in the 4G Core Network

In my previous column, I wrote about the opportunities Network Functions Virtualization (NFV) offers mobile operators, especially in the core network. (See 5 Opportunities for NFV in the 4G Core Network.)

In this piece, I discuss some of the reasons why NFV is not yet ready for prime time. I'm paraphrasing, of course, but in my work with mobile operator technology executives, I know these are the sentiments widely held by the people responsible for designing and operating 4G core networks.

In no particular order:

1. Immature technology and product availability: The performance of virtualized network functions (VNFs) is not yet equivalent to today's built-for-purpose products, or even sufficiently close to it. Reliability is also an unknown quantity and must be approached with a fundamentally different mindset. The even bigger challenge is that most operators are not close to being able to run VNFs in a "cloud" environment. This is a solvable problem, it's just too early.

2. Operational processes: You can have the most progressive CTO team in the world, but unless the proposed solution is accepted by the team responsible for running that part of the network, and making sure it hits the reliability and performance targets, it won't make much difference. Operators are used to buying "vertically assured" products from vendors that will stand by the box if something goes wrong. Changing this mindset at an abstract level is one thing. At an operational level it is quite another.

3. Investment cycle: Progressive operators have recently installed a new evolved packet core (EPC), and related core network elements, to support the introduction of LTE. Many have also recently closed tenders for IMS/VoLTE. It is out of the question to revisit these investments for at least the next three years. Any virtualized solution must be positioned with this market context very much in mind.

4. Adding new NFV platforms increases opex: Using a virtual EPC as part of a "cap and grow" strategy alongside the existing core network is commonly proposed. But while a parallel core network may make sense in terms of being able to experiment with NFV for less critical services, such as M2M, it also adds costs through duplication. This especially impacts operating costs and results in the exact opposite of what NFV promised at the outset -- reduced opex.

5. Need to identify use-cases: If the mobile network operator is basically in the business of selling Internet access, there are limited opportunities to do clever things in the services domain. So while NFV promises greater software-configurable service agility, without clear use-cases and revenue models, it's hard for mobile operators to make the business case. Whisper it, but in this respect NFV is a little like IMS.