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Hierarchy Level


Modify the size of the MAC address table for the bridge domain or VLAN, a set of bridge domains or VLANs associated with a trunk port, or a virtual switch. The default is 5120 MAC addresses.


For multichassis link aggregation (MC-LAG) peers in active-active mode, configuring the mac-table-size statement or changing the mac-table-size configuration when traffic is flowing can cause the MAC entries to be out of synchronization between the two MC-LAG peers, which might result in flooding. To avoid flooding, you must either halt traffic forwarding and then configure the mac-table-size statement or use the commit at configuration statement to commit the changes at the same time in both the peer nodes.

Alternatively, if flooding does occur, you can clear the bridge MAC table on both the routers by using the clear bridge mac-table command. Running this command ensures that the MAC entries are re-learned and in synchronization between both the peers.


limit—Specify the maximum number of addresses in the MAC address table.

  • Range: 16 through 1,048,575 MAC addresses

  • Default: 5120 MAC addresses

    There is no default MAC address limit for the mac-table-size statement at the [edit switch-options] hierarchy level. The number of MAC addresses that can be learned is only limited by the platform, 65,535 MAC addresses for EX Series switches and 1,048,575 MAC addresses for other devices.

The remaining statement is explained separately. See CLI Explorer.

Required Privilege Level

routing—To view this statement in the configuration.

routing-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 8.4.

Support for the switch-options statement added in Junos OS Release 9.2.

Support for top-level configuration for the virtual-switch type of routing instance added in Junos OS Release 9.2. In Junos OS Release 9.1 and earlier, the routing instances hierarchy supported this statement only for a VPLS instance or a bridge domain configured within a virtual switch.

Support for logical systems added in Junos OS Release 9.6.

[edit switch-options] and [edit vlans vlan-name switch-options] hierarchy levels introduced in Junos OS Release 12.3R2 for EX Series switches.

Support at the [edit vlans vlan-name switch-options hierarchy level introduced in Junos OS Release 13.2 for the QFX Series.