Packet Buffering to Minimize Service Downtime and Packet Loss During Redundancy Switchover

Availability is one of the key technical requirements for mission-critical communication services (e.g., emergency calls in telephone services), but traditional solutions depend on dedicated hardware or application-specific functions and tend to be less flexible and require large development costs. On the other hand, there is a growing number of use cases such as web services that require rapid development to keep up with evolving trends. In these use cases, it is desirable to be able to easily ensure high availability. One example method for achieving this is the use of reusable software for redundant system switching functions, such as checkpoint and restore in userspace (CRIU). However, many packets often lose due to the state transition between the active and standby systems. In this paper, we propose a “redundancy switchover support function” that provides high availability to minimize packet loss for the redundancy switchover between the active and standby systems. The proposed method minimizes packet loss by buffering arriving packets during the process of redundancy switchover, when writing out the status of the active system and starting up the standby system. In the evaluation using simple UDP forward applications and CRIU, we find that packet loss and service downtime can be reduced with only a small increase in latency.