When you install two Management Switch Fabric Module (MSM) or Management Modules (MMs) in a BlackDiamond chassis, one MSM/MM (node) assumes the role of primary and the other node assumes the role of backup.
Note
This section applies to Modular Switches and 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:
After you confirm the primary and backup nodes are synchronized, proceed to step 3 in STP and Hitless Failover--Modular Switches Only.
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, see the Feature License Requirements document.