In my previous article, I wrote about developments in virtual RAN, and indicated that the actual focus on the service providers is on core network migration strategies. The RAN receives high attention because it consumes more of the MNO capex and opex than the core network. This makes it a primary target for cost reduction. However, the core network strategy is where MNOs are placing their current emphasis because they understand the impact the core network architecture has on their business proposition and future viability.
In this article, together with my Xona business partner Dr. Riad Hartani, I address the evolution of the mobile core network and related complexities encountered in core migration projects we undertook with different service providers. The mobile core network in its broad definition includes the packet core, the services network, the mobile edge and the operating systems.
Packet Core Considerations
In dealing with the evolution of the mobile packet core, MNOs face a number of considerations to overcome of which we mention the following:
- Determining the underlying cloud and virtual infrastructure: private, public, hybrid cloud models, cloud OS, cloud management, etc. The choices related to storage, compute and networking infrastructure have direct impact on end-to-end network operations, for example, SLA and QoE management, cybersecurity architecture, and the associated economics.
- Choosing from a variety of 4G to 5G migration architectures that include standalone / non-standalone (SA/NSA) and the distribution of control and data planes in the context of end user devices evolution, radio network architecture evolution, and the multi-dimensional cost/performance trade-offs.
- With the core network at the heart of the overall mobile network, core network architecture is a function of the evolution of the surrounding functions which themselves are on a path of increased virtualization, agility and scalability. These functions include next generation OSS and BSS systems, the services components (e.g. IMS, roaming) and the policy components (e.g. PCRF). As a result, challenging considerations for interworking and end-to-end orchestration emerge.
- 5G offers a whole set of new service models that include private 5G networks, shared spectrum networks (CBRS), overlay or parallel IoT networks (3GPP and non-3GPP connectivity protocols) and mobile edge services (MEC) among many others. Enabling such service models economically requires additional rethink in the context of core network architecture that includes slicing, virtualization, and orchestration, among other aspects.
- The migration towards cloud-native functions for some of the core network elements as well as surrounding network components in the operation and service layers exposes operators to new dimensions. Operators need to deal with new application development environment including the orchestration and containerization models required for agile and distributed application development environments.
- New vendors in the core network, similar to those in the radio network, are attempting to leapfrog the incumbents. New models that leverage state-of-the-art NFV/SDN implementations such as network-as-a-service model and hosted-core, are forcing operators to rethink their choice of core solution providers.
Concluding Remarks
Having worked on the design and deployment of mobile core networks for over a decade, we witnessed the critical architectural aspects to consider in order to ensure optimal services offering and efficient investment protection. We are certain that in the era of multi-service and multi-application networks, operators will have to ensure that their network architecture decouples the different types of services to ensure service agility and ensure robustness in network operations. This is a critical point that will govern the migration of the core network going forward.
The core network is a small portion of the end-to-end network buildout in comparison with the RAN. Yet, getting it right is fundamental to achieving the deployment and service quality goals. We are witnessing a high-level of complexity in architecting the broad mobile core network at the moment, which could make or break the migration to 5G networks.