Configuring the Timer for the Backup Member to Start Using Its Own MAC Address as Primary of a Virtual Chassis

When a backup member takes control of a Virtual Chassis because of a reset or other temporary failure, the backup member uses the MAC address of the old primary switch as the system MAC base address. This process helps ensure a smooth transition of the primary role with no disruption to network connectivity.

The MAC persistence timer is used in situations in which the primary switch is no longer a member of the Virtual Chassis because it has been physically disconnected or removed. If the old primary switch does not rejoin the Virtual Chassis before the timer elapses, the new primary switch starts using its own MAC address as the system’s MAC base address. For information regarding how the system MAC base address is used to assign MAC addresses to ports in a Virtual Chassis, see Understanding MAC Address Assignment on a Virtual Chassis.

The default timer value is 10 minutes. The maximum timer value is 60 minutes.

You can disable the MAC persistence timer starting in Junos OS Release 12.1R3. When the MAC persistence timer is disabled, the MAC address of the old primary switch is used as the system MAC base address; no MAC address changes occur within the Virtual Chassis even when the old primary switch is no longer a member of the Virtual Chassis because it has been physically disconnected or removed.