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Hierarchy Level

Release Information

Statement introduced in Junos OS Release 9.6 for MX Series routers.

events statement introduced in Junos OS Release 11.4R4 for MX Series routers.

Statement introduced in Junos OS Release 12.2 for the QFX Series. Only the chassis-id, mc-ae-id, mode active-active, and status-control (active | standby) options are supported on QFX Series devices.

Statement introduced in Junos OS Release 12.3R2 for EX Series switches.

prefer-status-control-active statement introduced in Junos OS Release 13.2R1 for EX Series switches.

init-delay-time seconds statement introduced in Junos OS Release 13.2R3 for EX Series switches.

switchover-mode and revert-time statements introduced in Junos OS Release 13.3.

Support for logical systems introduced in Junos OS Release 14.1.


Enable multichassis link aggregation groups (MC-LAG), which enables one device to form a logical LAG interface with two or more other devices.


chassis-idSpecify the chassis ID for Link Aggregation Control Protocol (LACP) to calculate the port number of MC-LAG physical member links.

Values: 0 or 1

eventsSpecify an action if a specific MC-LAG event occurs.
iccp-peer-downSpecify an action if the ICCP peer of this node goes down.
force-icl-downIf the node’s ICCP peer goes down, bring down the interchassis-link logical interface.
prefer-status-control-activeSpecify that the node configured as status-control active become the active node if the peer of this node goes down.

When ICCP goes down, you can use this keyword to make a mc-lag PE to become the active PE. For example, if you want mc-lag PE1 to be Active on ICCP down, then configure this keyword in PE1. It is not recommended to configure this keyword in both the mc-lag PEs.


The prefer-status-control-active statement can be configured with the status-control standby configuration to prevent the LACP MC-LAG system ID from reverting to the default LACP system ID on ICCP failure. Use this configuration only if you can ensure that ICCP will not go down unless the router or switch is down. You must also configure the hold-time down value (at the [edit interfaces interface-name] hierarchy level) for the interchassis link with the status-control standby configuration to be higher than the ICCP BFD timeout. This configuration prevents data traffic loss by ensuring that when the router or switch with the status-control active configuration goes down, the router or switch with the status-control standby configuration does not go into standby mode.

To make the prefer-status-control-active configuration work with the status-control standby configuration when an interchassis-link logical interface is configured on aggregate Ethernet interface, you must either configure the lacp periodic interval statement at the [edit interface interface-name aggregated-ether-options] hierarchy level as slow or configure the detection-time threshold statement at the [edit protocols iccp peer liveness-detection] hierarchy level as less than 3 seconds.

init-delay-time secondsTo minimize traffic loss, specify the number of seconds in which to delay bringing the multichassis aggregated Ethernet interface back to the up state when you reboot an MC-LAG peer.

On QFX and EX Series switches, the default session establishment hold time is 300 seconds. However, the session establishment time must be at least 100 seconds higher than the init delay time. You can optionally update the session establishment time to be 340 seconds and the init delay time to be 240 seconds.

mc-ae-id mc-ae-idSpecify the identification number of the MC-LAG device. The two MC-LAG network devices that manage a given MC-LAG must have the same identification number.

Range: 1 through 65,535

mode (active-active | active-standby)Specify whether the MC-LAG is in active-active or active-standby mode.

You can configure IPv4 (inet) and IPv6 (inet6) addresses on mc-ae interfaces when the active-standby mode is configured.

redundancy-group group-idSpecify the redundancy group identification number. The Inter-Chassis Control Protocol (ICCP) uses the redundancy group ID to associate multiple chassis that perform similar redundancy functions.

Range: 1 through 4,294,967,294

revert-timeWait interval (in minutes) before the switchover to the preferred node is performed when the switchover-mode is configured as revertive.

Range: 1 through 10

status-control (active | standby)Specify whether the chassis becomes active or remains in standby mode when an interchassis link failure occurs.
switchover-mode (non-revertive | revertive)Specify whether Junos OS should trigger a link switchover to the preferred node when the active node is available.

For revertive mode to automatically switch over to the preferred node, the status-control statement should be configured as active.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.