VRRP and Hitless Failover

Note

This section applies to SummitStack only.

The primary node executes the switch‘s management functions, and the backup acts in a standby role. Hitless failover transfers switch management control from the primary to the backup and maintains the state of VRRP. While VRRP supports hitless failover, you do not explicitly configure hitless failover support; rather, if you have two nodes installed, hitless failover is available.

To support hitless failover, the primary node replicates VRRP protocol data units (PDUs) to the backup, which allows the nodes to run VRRP in parallel. Although both nodes receive VRRP PDUs, only the primary transmits VRRP PDUs to neighboring switches and participates in VRRP.

To initiate hitless failover on a network that uses VRRP:

Confirm that the primary and backup nodes are synchronized and have identical software and switch configurations using the show switch {detail} command.
The output displays the status of the nodes, with the primary node showing MASTER and the backup node showing BACKUP (InSync).
1. If the primary and backup nodes are not synchronized and both nodes are running a version of ExtremeXOS that supports synchronization, proceed to step 2 in STP and Hitless Failover—SummitStack Only.
2. If the primary and backup nodes are synchronized, proceed to step 3 in STP and Hitless Failover—SummitStack Only.
If the primary and backup nodes are not synchronized, use the synchronize command to replicate all saved images and configurations from the primary to the backup.
After you confirm the primary and backup nodes are synchronized, proceed to step 3 in STP and Hitless Failover—SummitStack Only.
If the primary and backup nodes are synchronized, use the run failover (formerly run msm-failover) command to initiate failover.

For more detailed information about verifying the status of the nodes and system redundancy, see Understanding System Redundancy. For more information about hitless failover, see Understanding Hitless Failover Support.

Note

For complete information about software licensing, including how to obtain and upgrade your license and what licenses are appropriate for these features, in the Switch Engine v33.1.1 Licensing Guide document.