# A Novel Framework for Cross-Cluster Scaling in Cloud-Native 5G NextGen Core
## 8 Conclusions and Future Work  
This paper presented a novel approach to the multi-site cloud native 5G capabilities in terms of vertical and horizontal scalability for Kubernetes clusters and cross-connectivity in different data centers by employing the Liqo operator to share resources. In this manner, we highlighted the on-demand network capacity, which is limited only by the number of utilized resources and clusters in the current testbed, as well as the programability of the network and mobile core configuration by leveraging the benefits of APIs. To complement the full stack of the MANO framework, a service mesh solution was integrated to ensure observability and monitoring for each service. Moreover, this proposed design is enriched with the CI/CD capabilities of a cloud-native solution that eases the deployment and integration of components compared to the MANO framework. Due to the increase in traffic and different vertical needs in terms of QoS, the proposed approach could bring not only cost savings to MNOs but also improve network performance along with a higher computational power that can be triggered upon request as well as high availability and fault tolerance of the infrastructure ensured by the cloud provider. In our setup, we analyze two peering scenarios (out-of-band and in-band) for offloading of both user and control planes. The aim of this paper was also to provide insight into inter-service monitoring; therefore, the above measurements were validated through a service-mesh monitoring solution dedicated to cloud-native applications. In addition, we analyze the response and request throughput of the AMF and SMF across data centers to demonstrate the system's performance. We observed that maximum registered values for the AMF request throughput offloaded user plane and control plane measured at the outbound source are two times higher than the AMF response throughput measured at the destination for the offloaded control plane, whereas the values registered for the SMF request throughput for both user and control planes are twice or three times higher for the SMF request throughput registered on the outbound source interface. Since SMF is responsible for the AMF selection, higher values for the SMF throughput are achieved for the offloaded control plane in the remote clusters. In addition, we determined the latency for the three UPF tunnels and the end-to-end user latency for three instantiated network slices. We observed that for in-band peering where a VPN tunnel is established, the user plane latency and the achieved throughput for two offloaded user plane functions have similar values compared to the latency registered for the UPF deployed in the local cluster, which is by 100 Mbit/s lower than the registered latency for the other two user plane functions. In terms of the measured end-to-end latency for the user connectivity to the Internet, the latency for all three configured network slices is slightly lower (by 1-2 ms) in the case of the in-band peering. As a proposed future work, our goal is to replicate the deployment across different public cloud providers, addressing the proposed test scenarios in a different setup using a physical RAN solution. Furthermore, we can also extend the end-to-end network slicing to new use cases for 6G to serve vertical demands, such as streaming, IoT, and vehicular communication, to validate the level of service guarantee accommodating different vertical demands. Conceptualization, O.-M.D.-G. and V.C. ; methodology, O.-M.D.-G. and V.C. ; software, O.-M.D.-G.; validation, V.C. and R.K.; formal analysis, O.-M.D.-G.; investigation, O.-M.D.-G.; resources, O.-M.D.-G.; data curation, O.-M.D.-G. and V.C. ; writing--original draft preparation, O.-M.D.-G.; writing--review and editing, O.-M.D.-G.; visualization, O.-M.D.-G.; supervision, V.C. and R.K.; project administration, V.C. ; funding acquisition, V.C. and R.K. All authors have read and agreed to the published version of the manuscript.