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Layer 2 Features

  • Configure MAC learning priority and enable persistent MAC learning on trunk interfaces (EX4100-48MP, EX4100-24MP, EX4100-48P, EX4100-48T, EX4100-24P, EX4100-24T, EX4100-F-48P, EX4100-F-24P, EX4100-F-48T, EX4100-F-24T, EX4100-F-12P, EX4100-F-12T, EX4300-MP, EX4400-24MP, EX4400-24P, EX4400-24T, EX4400-48F, EX4400-48MP, EX4400-48P, and EX4400-48T)—Starting in Junos OS Release 22.4R1, you can configure MAC learning priority on the interfaces so that the high-priority interface always learns the MAC addresses. Configuring MAC learning priority ensures:

    • Traffic sent to the high-priority interface that learns the MAC address is accepted.

    • Traffic with the same MAC address sent to the low-priority interface is dropped.

    By default, the switch discards the traffic if you do not configure an explicit action.

    MAC address move is allowed when you configure the interfaces with the same MAC learning priority. When interfaces are not configured with MAC learning priority, then the default priority for each interface is 4. By default, discard action is taken if an explicit action is not configured. To configure MAC learning priority, use the mac-learning-priority configuration statement at the [edit switch-options interface interface-name] hierarchy level.

    To accept traffic on the low-priority interface, you need to configure persistent MAC learning on the high-priority interface.


    Do not configure both MAC learning priority and persistent MAC learning on the same interface.

    From Junos OS Release 22.4R1 onward, you can enable persistent MAC learning on the trunk or vlan-tagged interfaces so that traffic is accepted on the low-priority interface.

    [See Configuring MAC Learning Priority.]