Enabling containerized Central Unit live migration in 5G radio access network: An experimental study

5G mobile networks have gained considerable attention and traction by offering numerous benefits such as high data rates, low latency, reliability, and application specific connectivity. To effectively achieve these milestones mobile network functions must be virtualized using Virtual Machine (VM) and/or Containers. The latter has gained momentum in recent years due to its reduced resource usage and virtualization overhead, improving efficiency and flexibility while sharing compute and network resources. While containerization offers numerous benefits, it still faces specific challenges, one of them being the ability to provide robustness and resiliency of the containerized network functions under challenging network conditions, e.g., varying load conditions and application types. The currently available open-source container platform(s) do not achieve a full-fledged containerized mobile network protocol stack as they fail to support successful live migration of containers that execute specific 5G software functionalities. The contribution of this study is to present a proof-of-concept implementation that completes the live migration of a containerized 5G Central Unit (CU) module between two servers without causing permanent service disruption to the mobile user. The authors' implementation makes use of an open-source migration software (CRIU) that has been modified to support the protocol (SCTP) used by the CU to exchange signaling messages with other 5G modules. The authors' implementation is experimentally tested in a federated testbed environment by applying four container migration techniques, namely Cold, Pre-Copy, Post-Copy, and HybridCopy migration. A performance comparison reveals that the end-user service recovery time due to the CU live migration can be reduced by up to 36% when applying the hybrid migration technique compared to the conventional cold migration technique. Additionally, experimental results reveal that compared to state-of-theart VM migration the container-based migration approach reduces both migration time and service downtime by 96.7% and 75.2%, respectively.