This describes how to update the system MAC address, when mac-persistence-timer is disabled.

The disable command has been available from Junos OS 12.1R3 to disable mac-persistence-timer , which retains the system MAC address of the virtual chassis. For more information, refer to KB25650 - [EX] The maximum timer value of 'mac-persistence-timer' has been changed from 12.1R3 or later [juniper.net] .

Initially, based on the MAC address of the primary, the system MAC address is selected. However, if mac-persistence-timer is disabled, the system MAC address will never change; even if primary has to be replaced.

If there is no risk of a duplicate MAC address, you can continuously use the system MAC address, based on the previous primary that was replaced. However, if you would like to use the previous primary in the network, but not as a member of the virtual chassis, the system MAC address has to be updated.

To update the system MAC address, use any of the following methods during maintenance time. These methods may affect the traffic that passes through the virtual chassis:

Method 1:

Reboot the whole chassis in the virtual chassis.

If this is not possible to be implemented then please use Method 2 or Method 3.
If you are using the following versions, please use Method 4 as mac-persistence-timer 0 is not supported due to an issue reported in PR858330 .

Method 2 :

1. Configuration change:

   deactivate virtual-chassis mac-persistence-timer disable
   set virtual-chassis mac-persistence-timer 0
   commit

2. Restart chassis by using the restart chassis-control command.

• Recover the configuration:
  

  delete virtual-chassis mac-persistence-timer 0
  activate virtual-chassis mac-persistence-timer disable
  commit
  

Method 3 :

1. Configuration change:
   

   deactivate virtual-chassis mac-persistence-timer disable
   set virtual-chassis mac-persistence-timer 0
   commit

2. Reboot the new primary.

• Recover the configuration:

  delete virtual-chassis mac-persistence-timer 0
  activate virtual-chassis mac-persistence-timer disable
  commit
  
  

Method 4 :

1. Configuration change:

   deactivate virtual-chassis mac-persistence-timer disable
   set virtual-chassis mac-persistence-timer 1
   commit

2. Restart chassis by using the restart chassis-control command.

• Wait for 1 minute or longer:

• Recover the configuration:
  

  delete virtual-chassis mac-persistence-timer 1
  activate virtual-chassis mac-persistence-timer disable
  commit
  

• KB25650 - [EX] The maximum timer value of 'mac-persistence-timer' has been changed from 12.1R3 or later [juniper.net]