Configuring Aggregated Ethernet LACP

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). You can configure different periodic rates on active and passive interfaces. When you configure the active and passive interfaces at different rates, the transmitter honors the receiver’s rate.

To force active and standby links within an aggregated Ethernet, you can configure LACP link protection and system priority at the aggregated Ethernet interface level using the link-protection and system-priority statements. Configuring values at this level results in only the configured interfaces using the defined configuration. LACP interface configuration also enables you to override global (chassis) LACP settings.

LACP link protection also uses port priority. You can configure port priority at the Ethernet interface [ether-options] hierarchy level using the port-priority statement. If you choose not to configure port priority, LACP link protection uses the default value for port priority (127).

To enable LACP link protection for an aggregated Ethernet interfaces, use the link-protection statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level:

[edit interfaces aeX aggregated-ether-options lacp]
link-protection;
    disable;
    revertive;
    non-revertive;
}

By default, LACP link protection reverts to a higher-priority (lower-numbered) link when that higher-priority link becomes operational or a link is added to the aggregator that is determined to be higher in priority. However, you can suppress link calculation by adding the non-revertive statement to the LACP link protection configuration. In nonrevertive mode, once a link is active and collecting and distributing packets, the subsequent addition of a higher-priority (better) link does not result in a switch and the current link remains active.

If LACP link protection is configured to be nonrevertive at the global ([edit chassis] hierarchy) level, you can add the revertive statement to the LACP link protection configuration to override the nonrevertive setting for the interface. In revertive mode, the addition of a higher-priority link to the aggregator results in LACP performing a priority recalculation and switching from the current active link to the new active link.

To configure LACP system priority for aggregated Ethernet interfaces on the interface, use the system-priority statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level:

[edit interfaces aeX aggregated-ether-options lacp]
system-priority;

The system priority is a 2-octet binary value that is part of the LACP system ID. The LACP system ID consists of the system priority as the two most-significant octets and the interface MAC address as the six least-significant octets. The system with the numerically lower value for system priority has the higher priority. By default, system priority is 127, with a range of 0 to 65,535.

To configure the LACP system identifier for aggregated Ethernet interfaces, use the system-id statement at the [edit interfaces aeX aggregated-ether-options lacp] hierarchy level:

[edit interfaces aeX aggregated-ether-options lacp]
system-id system-id;

The user-defined system identifier in LACP enables two ports from two separate devices to act as though they were part of the same aggregate group.

The system identifier is a 48-bit (6-byte) globally unique field. It is used in combination with a 16-bit system-priority value, which results in a unique LACP system identifier.

To configure an administrative key for LACP, include the admin-key number statement at the edit interfaces aex aggregated-ether-options lacp] hierarchy level:

[edit interfaces ae x aggregated-ether-options-lacp]
admin-key number;

To configure LACP port priority for aggregated Ethernet interfaces, use the port-priority statement at the [edit interfaces interface-name ether-options 802.3ad aeX lacp] or [edit interfaces interface-name ether-options 802.3ad aeX lacp] hierarchy levels:

[edit interfaces interface-name ether-options 802.3ad aeX lacp]
port-priority priority;

The port priority is a 2-octet field that is part of the LACP port ID. The LACP port ID consists of the port priority as the two most-significant octets and the port number as the two least-significant octets. The system with the numerically lower value for port priority has the higher priority. By default, port priority is 127, with a range of 0 to 65,535.

Port aggregation selection is made by each system based on the highest port priority and are assigned by the system with the highest priority. Ports are selected and assigned starting with the highest priority port of the highest priority system and working down in priority from there.

To trace the operations of the LACP process, include the traceoptions statement at the [edit protocols lacp] hierarchy level:

[edit protocols lacp]
traceoptions {
    file <filename> <files number> <size size> <world-readable | no-world-readable>;
    flag flag;
    no-remote-trace;
}

You can specify the following flags in the protocols lacp traceoptions statement:

• all—All LACP tracing operations

• configuration—Configuration code

• packet—Packets sent and received

• process—LACP process events

• protocol—LACP protocol state machine

• routing-socket—Routing socket events

• startup—Process startup events

LACP can link together multiple different physical interfaces, but only features that are supported across all of the linked devices will be supported in the resulting link aggregation group (LAG) bundle. For example, different PICs can support a different number of forwarding classes. If you use link aggregation to link together the ports of a PIC that supports up to 16 forwarding classes with a PIC that supports up to 8 forwarding classes, the resulting LAG bundle will only support up to 8 forwarding classes. Similarly, linking together a PIC that supports WRED with a PIC that does not support it will result in a LAG bundle that does not support WRED.