Externalizing State in Radio Access Network : A Quantitative Evaluation of Local and Externalized State Management

Sammanfattning

Different state management approaches and standby configurations can affect how traffic is handled during failovers in a Radio Access Network (RAN). This thesis investigates state externalization in a RAN-inspired environment and how different state management approaches affect throughput, packet loss, and recovery time during normal operation and during failover. To evaluate this, a prototype was implemented using evgen to simulate a RAN-like traffic handling function. The implementation compares a local state approach, where state is maintained within the function instance, with an externalized state approach using a shared state store. Different failover scenarios were also evaluated by comparing cold standby and hot standby takeovers. The results showed that the local state had slightly higher throughput during normal operation, while the externalized state showed higher packet loss. During failover, the externalized state showed slightly lower throughput degradation along with decreased packet loss relative to its baseline compared to the local state. When comparing cold standby and hot standby takeovers, hot standby showed a shorter recovery time. Since the evaluation was performed in a controlled prototype environment, the results should be interpreted within the limitations of the implementation. Ideas for future research are also presented.