You can configure LACP link protection and system priority at the global level on the switch or for a specific aggregated Ethernet interface. When using LACP link protection, you can configure only two member links for an aggregated Ethernet interface: one active and one standby. LACP link protection ensures that only one link—the link with the higher priority—is used for traffic. The other link is forced to stay in a waiting state.

By default LACP link protection reverts to a higher-priority (lower-numbered) link when the higher-priority link becomes operational or when a higher-priority link is added to the aggregated Ethernet bundle. However, you can suppress link calculation by adding the non-revertive statement to the link protection configuration. In nonrevertive mode, when a link is active in sending and receiving LACP packets, adding a higher-priority link to the bundle does not change the status of the currently active link. It remains active.

If LACP link configuration is specified to be nonrevertive at the global [edit chassis] hierarchy level, you can specify the revertive statement in the LACP link protection configuration at the aggregated Ethernet interface level to override the nonrevertive setting for the interface. In revertive mode, adding a higher-priority link to the aggregated Ethernet bundle results in LACP recalculating the priority and switching the status from the currently active link to the newly added, higher-priority link.

Note: When LACP link protection is enabled on both local and remote sides of the link, both sides must use the same mode (either revertive or nonrevertive).

Configuring LACP link configuration at the aggregated Ethernet level results in only the configured interfaces using the defined configuration. LACP interface configuration also enables you to override global (chassis) LACP settings.

Before you configure LACP link protection, be sure you have:

• Configured the aggregated Ethernet bundles—also known as link aggregation groups (LAGs). See Configuring Aggregated Ethernet Links (CLI Procedure).
• Configured LACP for the interface. See Configuring Aggregated Ethernet LACP (CLI Procedure).

You can configure LACP link protection for all aggregated Ethernet interfaces on the switch by enabling it at the global level on the switch or configure it for a specific aggregated Ethernet interface by enabling it on that interface.

• Configuring LACP Link Protection at the Global Level
• Configuring LACP Link Protection at the Aggregated Interface Level

1. Enable LACP link protection on the switch:
   [edit chassis aggregated-devices ethernet lacp]
user@switch# set link-protection
2. (Optional) Configure the LACP link protection for the aggregated Ethernet interfaces to be in nonrevertive mode:

   Note: LACP link protection is in revertive mode by default.

   [edit chassis aggregated-devices ethernet lacp link-protection]
user@switch# set non-revertive
3. (Optional)To configure LACP system priority for the aggregated Ethernet interfaces:
   [edit chassis aggregated-devices ethernet lacp]
user@switch# set system-priority

To enable LACP link protection for a specific aggregated Ethernet interface: