Specifying Minimum Active Links for LACP

Link Aggregation Control Protocol (LACP) allows the operator to configure a minimum number of active member links in a trunk group to remain operational. When the number of active member links in the trunk is less than the configured threshold value, the LACP trunk will be shut down. An additional option is provided to configure an enable-timer, on expiry of which the LACP trunk brought down by the min-active-links functionality, will be re-enabled. Once the trunk member ports are re-enabled, the validation for the active links against the configured threshold is performed after a minute and the trunk state will be decided accordingly. The trunk will be up and the traffic will be forwarded though the LACP trunk during this period.

  • If the minimum active links are configured without enable-timer configuration, the LACP trunk disabled by the feature will remain down until the operator explicitly disables and re-enables the port or triggers a port up indication by any alternative means.

  • If the number of active links in a LACP trunk is less than the threshold value, the trunk will not be functional and traffic will not pass through the respective trunk.

  • If the number of active links in the trunk drops below the threshold, the entire trunk will be brought down and complete traffic flowing through the same will be dropped. Hence, this configuration must be used carefully in a topology where there is a redundant traffic path.

  • It is recommended to configure the min-active-links on one side of the trunk.