In many ways, network slicing features of coming 5G-compliant core networks builds on evolved packet core (EPC), the current framework for providing converged voice and data on a 4G Long-Term Evolution (LTE) network. The 2G and 3G networks use a different architecture, using
circuit-switched networks for voice and packet-switched networks for data.
Evolved packet core uses Internet Protocol, which is simpler and media independent. Standards for EPC were developed by the Third Generation Partnership Project (3GPP) in early 2009.
As always is the case, networking professionals can disagree about whether NFV either “improves or replaces” the EPC. Perhaps most would argue that NFV extends and builds upon EPC.
It might be somewhat subtle, but CIMI principal Tom Nollte says network slicing (a feature of 5G-compliant core networks) could have an impact in terms of “eliminating the expensive evolved packet core infrastructure that handles mobility in 4G networks.”
Most would probably argue that NFV virtualizes the EPC function. But that is where the nuances are important. If EPC is virtualized, is that a functional replacement of EPC by NFV networks using network slicing? It’s subtle. It might be most accurate to say that virtual replaces physical in the area of EPC functioning.
EPC also separates the control plane from the user plane, where control network is separate from the actual payload data, a move intended to reduce costs and network overhead, while improving ability to scale networks more easily (and at less cost) by reducing the amount of active elements.
The next evolution, many would argue, is network functions virtualization (NFV), a network architecture concept that uses “information technology” approaches to virtualize entire classes of network node functions, making them building blocks that can be connected or chained together to create communication services.
One way to look at such an NFV network is that the business case can drive the configuration of network capabilities for each specific application (at least to the extent the network can be customized for latency, security, geography, bandwidth or quality). Historically, the goal of every next-generation network was to create the ability for bandwidth on demand, something NFV builds on, but augments.
So it might be an irrelevant argument (“how many angels can stand on the head of a pin”), but virtualizing networks using network slicing and NFV might either been seen as “improving” existing network functions, or as “replacing” them.