SDN-based vs. software-only EPC gateways: A cost analysis

Technologies like software defined networking and cloud computing allow for new approaches in mobile network design. A key driver for bringing mobile networks into the cloud is the expected cost reduction resulting from economies of scale: all software run on commercial off-the-shelf server which can be accumulated in one or more datacenters with all of those having a similar setup, minimizing the administrative costs. Deploying mobile core control functions as applications in datacenters already proved to be viable and economic. However, the evolved packet core (EPC), which mostly comprises gateways, holds a special challenge, since there is a strong interaction between forwarding plane and control functions. Having those functions as application software running on servers in datacenters induces the risk that cost reductions from virtualization are offset by costs of additional transport and processing. This paper analyzes the total cost of ownership of several variants of virtualized EPC gateways for a country-scale mobile network covering Japan. The cost model presented can serve as guideline to understand the economic aspects of future virtual network function deployments.