Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Configuring LACP Link Protection of Aggregated Ethernet Interfaces for Switches

 

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 to protect a single link in the aggregated ethernet bundle, you 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.

When using LACP link protection to protect multiple links in an aggregated ethernet bundle, you configure links into primary and backup subgroups. A link protection subgroup is a collection of ethernet links within the aggregated ethernet bundle. When you use link protection subgroups, you configure a primary subgroup and a backup subgroup. The configuration process includes assigning member links to each subgroup. When the configuration process is complete, the primary subgroup is used to forward traffic until a switchover event, such as a link failure, occurs and causes the backup subgroup to assume control of traffic that was travelling on the links in the primary subgroup within the bundle.

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. For priority purposes, LACP link protection treats subgroups like links. 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:

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.

To configure LACP link protection for aggregated Ethernet interfaces at the global 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:

  1. Enable LACP link protection for the interface:
    [edit interfaces aeX aggregated-ether-options lacp]

    user@switch# set link-protection
  2. (Optional) Configure the LACP link protection for the aggregated Ethernet interface to be in revertive or nonrevertive mode:
  3. (Optional)To configure LACP system priority for an aggregated Ethernet interface:
    [edit interfaces aeX aggregated-ether-options lacp link-protection]

    user@switch# set system-priority
  4. (Optional) To configure LACP port priority for an aggregated Ethernet interface:
    [edit interfaces ge-fpc/pic/port ether-options 802.3ad lacp]

    user@switch# set port-priority

You can configure link protection subgroup bundles to provide link protection for multiple links in an aggregated ethernet bundle.

Link protection subgroups allow you to provide link protection to a collection of Ethernet links within a LAG bundle, instead of providing protection to a single link in the aggregated ethernet bundle only. You can, for instance, configure a primary subgroup with three member links and a backup subgroup with three different member links and use the backup subgroup to provide link protection for the primary subgroup.

To configure link protection using subgroups:

  1. Configure the primary link protection subgroup in the aggregated ethernet interface:
    [edit interfaces aeX aggregated-ether-options]

    user@switch# set link-protection-sub-group group-name primary

    For instance, to create a primary link protection subgroup named subgroup-primary for interface ae0:

    [edit interfaces ae0 aggregated-ether-options]

    user@switch# set link-protection-sub-group subgroup-primary primary
  2. Configure the backup link protection subgroup in the aggregated ethernet interface:
    [edit interfaces aeX aggregated-ether-options]

    user@switch# set link-protection-sub-group group-name backup

    For instance, to create a backup link protection subgroup named subgroup-backup for interface ae0:

    [edit interfaces ae0 aggregated-ether-options]

    user@switch# set link-protection-sub-group subgroup-backup backup
    Note

    You can create one primary and one backup link protection subgroup per aggregated ethernet interface.

  3. Attach interfaces to the link protection subgroups:
    [edit interfaces interface-name ether-options 802.3ad]

    user@switch# set link-protection-sub-group group-name
    Note

    The primary and backup link protection subgroups must contain the same number of interfaces. For instance, if the primary link protection subgroup contains three interfaces, the backup link protection subgroup must also contain three interfaces.

    For instance, to configure interfaces ge-0/0/0 and ge-0/0/1 into link protection subgroup subgroup-primary and interfaces ge-0/0/2 and ge-0/0/3 into link protection subgroup subgroup-backup:

    [edit interfaces ge-0/0/0 ether-options 802.3ad]

    user@switch# set link-protection-sub-group subgroup-primary


    [edit interfaces ge-0/0/1 ether-options 802.3ad]

    user@switch# set link-protection-sub-group subgroup-primary


    [edit interfaces ge-0/0/2 ether-options 802.3ad]

    user@switch# set link-protection-sub-group subgroup-backup


    [edit interfaces ge-0/0/3 ether-options 802.3ad]

    user@switch# set link-protection-sub-group subgroup-backup
  4. (Optional) Configure the port priority for link protection:
    [edit interfaces interface-name ether-options 802.3ad]

    user@switch# set port-priority priority

    The port priority is used to select the active link.

  5. Enable link protection

    To enable link protection at the LAG level:

    [edit interfaces aeX aggregated-ether-options]

    user@switch# set link-protection
    Note

    ACX Series routers do not support static link protection.

    To enable link protection at the LACP level:

    [edit interfaces aeX aggregated-ether-options lacp]

    user@switch# set link-protection

    For instance, to enable link protection on ae0 at the LAG level:

    [edit interfaces ae0 aggregated-ether-options]

    user@switch# set link-protection

    For instance, to enable link protection on ae0 at the LACP level:

    [edit interfaces ae0 aggregated-ether-options lacp]

    user@switch# set link-protection
Note

The LACP decides active and back up state of links. When configuring LACP, the state of the backup link should not be configured manually as down. The following command is not supported if LACP is configured:set interfaces ae0 aggregated-ether-options link-protection backup-state down

Related Documentation