5G Stateful Session Recovery

Required License: 5G Correlation

5G stateful session recovery provides session persistence for GigaSMART 5G applications, including 5G flow filtering, 5G forward listing, and 5G flow sampling. In this method of recovery, 5G sessions are backed up periodically so that they can be recovered faster after a GigaSMART line card reboot or a node reboot.

5G stateful session recovery requires additional memory for storing backups. GigaVUE‑HC3 has the required memory. For GigaVUE‑HC2, Control Card version 2 (HC2 CCv2) is required. Contact your Sales representative or authorized partner for the required control cards for GigaVUE‑HC2.

Using 5G stateful session recovery, the 5G session tables in the GigaSMART line card memory is periodically backed up to the control card memory on the node and stored.

You should configure an interval for how often the backups occur, such as every 10 minutes. If 5G stateful session recovery is enabled and the GigaSMART line card is rebooted, the 5G session tables is restored automatically following the reboot.

The last stored backup file is downloaded from the control card to the GigaSMART line card using FTP. The session table is repopulated from the last stored backup file to each GigaSMART engine, up to 8 engines. Packet count statistics for sessions are saved and restored.

Depending on the size of the session table, the amount of time to restore from the backup might take as much as 3 minutes. During that interval, traffic is blocked to the virtual port on the GigaSMART line card. Once the session table is read and populated, traffic is allowed.

Depending on the interval between backups, there could be differences between the stored state and the current state of the system, for example, map configuration could change, or sessions could be added, modified, or deleted.

Load balancing information is not persisted, so after a session table is repopulated, a session that was once sent to one load balanced port may be sent to a different load balanced port after the reboot. However, for SUPI-based load balancing, the traffic is sent to the same port as it was before the reboot.

5G stateful session recovery works in a cluster environment; however, the cluster leader must remain the same.