Service Availability in the NFV Virtualized Evolved Packet Core

Network Function Virtualization (NFV) promises to transform the way telecom providers design and operate networks and network services. Virtualized Evolved Packet Core (vEPC) is one of the NFV use cases that has got most attention, where dependability is a major concern. In the traditional EPC, functions are deployed in proprietary network elements with proven characteristics, e.g., a defined availability, and corresponding guarantees. Hence, network operators have a firm basis for the design of a robust mobile core network. On the other hand, in the vEPC, network operators face a more challenging environment, where functions, subsystems and requirements are interrelated in a more complex manner. Hence, the assessment of the network robustness, and the design to meet dependability requirements become hard. In order to address this challenge, we provide initial guidelines to model system availability in vEPC scenarios, we propose a stochastic activity networks dependability model to assess it, and finally, we identify the most relevant factors to be considered by providers to fulfill the demanding dependability requirements of the mobile core.