  The Fifth Generation (5G) mobile core network is designed as a set of Virtual
Network Functions (VNFs) hosted on Commercial-Off-the-Shelf (COTS) hardware.
This creates a growing demand for general-purpose compute resources as 5G
deployments continue to expand. Given their elastic infrastructure, cloud
services such as Amazon Web Services (AWS) are attractive platforms to address
this need. Therefore, it is crucial to understand the control and user plane
Quality of Service (QoS) performance associated with deploying the 5G core on
top of a public cloud. To account for both software and communication costs, we
build a 5G testbed using open-source components spanning multiple locations
within AWS. We present an operational breakdown of the performance overhead for
various 5G use cases using different core deployment strategies. Our results
indicate that moving specific VNFs into edge regions reduces the latency
overhead for key 5G operations. Furthermore, we instantiated multiple user
plane connections between availability zones and edge regions with different
traffic loads. We observed that the deterioration of connection quality varies
depending on traffic loads and is use case specific. Ultimately, our findings
provide new insights for Mobile Virtual Network Operators (MVNOs) for optimal
placements of their 5G core functions.
