Configure Aggregated Ethernet LACP

For untagged, aggregated Ethernet interfaces, you can configure the Link Aggregation Control Protocol (LACP). LACP allows you to bundle several physical interfaces to form one logical interface. LACP exchanges are made between actors and partners. An actor is the local interface in an LACP exchange. A partner is the remote interface in an LACP exchange.

LACP is defined in IEEE 802.3ad, Aggregation of Multiple Link Segments.

LACP was designed to achieve the following:

• Automatic addition and deletion of individual links to the aggregate bundle without user intervention.
• Link monitoring to check whether both ends of the bundle are connected to the correct group.

The JUNOS implementation of LACP provides link monitoring but not automatic addition and deletion of links.

By default, LACP is not enabled on aggregated Ethernet interfaces. To enable LACP, include the lacp statement at the [edit interfaces interface-name aggregated-ether-options] hierarchy level:

[edit interfaces interface-name aggregated-ether-options]

lacp mode;

The mode can be active or passive. To initiate transmission of LACP packets and respond to LACP packets, configure active mode. If the actor and partner are both in passive mode, they do not exchange LACP packets. If either the actor or partner is active, they do exchange LACP packets.

By default, the actor and partner send LACP packets every second. You can configure the interval at which the interfaces send LACP packets by including the periodic statement at the [edit interfaces interface-name aggregated-ether-options lacp] hierarchy level:

[edit interfaces interface-name aggregated-ether-options lacp]

periodic interval;

The interval can be fast (every second) or slow (every 30 seconds). The slow interval configuration takes precedence over the fast interval. If you configure either the actor or the partner to send LACP packets at the slow interval, then both the actor and partner send packets at the slow interval, even if you explicitly configure one interface to send packets at the fast interval.