VSF behavior

VSF is always enabled on supported switches. Within the stack, one switch is the Master that runs all control plane software and manages the ASICs of all stack members. Any switch apart from primary can be configured as Standby switch.

Each stack member must have a unique member number. When deploying a stack, ensure that each member has a distinct number by renumbering the switches to the appropriate member numbers. Stack formation will fail if there is a member number conflict.
  • The primary member will become Master and the secondary member will become Standby under normal circumstances.

  • The primary member is member number 1. This setting is not configurable and 1 is the default. A factory-default switch boots up as a VSF-enabled switch with a member number of 1.

  • The secondary member number is user configurable, and there is no default secondary member. It is recommended that the customer configures a secondary member in the stack, since a stack with a standby offers resiliency and high-availability.

  • No members other than primary and secondary members can become Master or Standby of the stack.


In a standard deployment, uplinks should be from primary and secondary. The management interface from primary and secondary members should be connected to the management network, providing management connectivity to the current master.