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.

To enable 5G stateful session recovery, as well as to configure timers, do the following:

1.   On the left navigation pane, click , and then select Physical>Nodes.
2. From the device view, select GigaSMART > GigaSMART groups.
3. Click on the alias of the GigaSMART group.
4. Select GTP Persistencein the GTP Persistence fields under GigaSMART Parameters as shown in the Figure 1. The timers are pre-configured with default values.

Figure 34 GTP Persistence GigaSMART Parameters

Use the System widget on the Overview page to determine the amount of memory. The size of memory is 24Gb in an upgraded system.

To view the System information, select Overview from the Navigation pane. The amount of free and used memory is displayed in the Memory field.

To view backup and restore information for GTP Persistence:

1.   Select GigaSMART > GigaSMART Groups > GigaSMART Group.
2. Click on the alias of the GigaSMART group.

A Quick View appears for the selected GigaSMART group.

3. Scroll down to GTP Persistence. In Figure 2 GTP Persistence Information, GigaSMART Group gsgrp-1_4_e1 is selected and the Quick View is displayed.

Figure 35 GTP Persistence Information

The following table describes persistence information.

Table 1: GigaSMART GTP Persistence Information

Name

Format

Backup Info

Backup file name

The internal name of the backup file.

Last successful time

The time stamp of the last successful backup.

Last fail time

The time stamp of the last failed backup.

Number of control tunnels

The number of control tunnels backed up.

Number of user tunnels

The number of user tunnels backed up.

Number of sessions

The number of sessions backed up.

Number of success

The number of successful backups.

Number of failed

The number of failed backups.

Config Status

The status of a backup, which is either Enabled or Disabled.

In Progress

The progress, which is either Yes or No.

Restore Info

Last restore time

The time stamp of the last restore.

Number of tunnels

The number of tunnels restored.

Number of sessions

The number of sessions restored.

To delete backup files, do the following:

1.   Select the alias of GigaSMART Group.
2. Click Edit.
3. Scroll down to GTP Persistence (refer to Figure 3)
4. Click Delete All under GTP Backup Files.

Figure 36 GTP Backup Files Delete