Near-Optimal Placement of Virtualized EPC Functions with Latency Bounds

The proliferation of mobiles devices, application sprawl, and
the ever-increasing data volume generates significant stress on cellular
networks and particularly on the cellular core, also known as the
Evolved Packet Core (EPC), i.e., the cellular network component residing
between the radio access network and the Internet. This is further
exacerbated by the deployment of hardware appliances for the implementation
of a wide range of network functions (e.g., gateways, mobility
management, firewalls, network address translation), hindering any
opportunity for elastic provisioning, and eventually leading to high operational
costs and a significant degree of load imbalance across the EPC.
Network Function Virtualization (NFV) has been seen a promising
solution in order to enable elasticity in the cellular core. Applying NFV
to the EPC raises the need for network function (NF) placement, which
in turn entails significant challenges, due to the stringent delay budgets
among cellular core components and the coexistence of communicating
data and control plane elements. To address these challenges, we
present a linear programming (LP) formulation for the computation of
NF placements that strikes a balance between optimality and time complexity.
Our evaluation results show that the LP achieves significantly
better load balancing, request acceptance rate, and resource utilization
compared to a greedy algorithm that performs NF placement inline with
carriers’ common practice today.