  Experimentation in practical, end-to-end (E2E) next-generation networks
deployments is becoming increasingly prevalent and significant in the realm of
modern networking and wireless communications research. The prevalence of
fifth-generation technology (5G) testbeds and the emergence of developing
networks systems, for the purposes of research and testing, focus on the
capabilities and features of analytics, intelligence, and automated management
using novel testbed designs and architectures, ranging from simple simulations
and setups to complex networking systems; however, with the ever-demanding
application requirements for modern and future networks, 5G-and-beyond (denoted
as 5G+) testbed experimentation can be useful in assessing the creation of
large-scale network infrastructures that are capable of supporting E2E
virtualized mobile network services. To this end, this paper presents a
functional, modular E2E 5G+ system, complete with the integration of a Radio
Access Network (RAN) and handling the connection of User Equipment (UE) in
real-world scenarios. As well, this paper assesses and evaluates the
effectiveness of emulating full network functionalities and capabilities,
including a complete description of user-plane data, from UE registrations to
communications sequences, and leads to the presentation of a future outlook in
powering new experimentation for 6G and next-generation networks.
