58BFD packets. When the link is recovered and the local port is placed in the Selected state again, thelocal port establishes a new session with the peer port. BFD notifies the Ethernet link aggregationmodule that the peer port is reachable. Because BFD provides fast failure detection, the local andpeer systems of a dynamic aggregate link can negotiate the aggregation state of their memberports faster.To enable BFD for an aggregation group:Step Command Remarks1. Enter system view. system-view N/A2. Enter aggregateinterface view.• Enter Layer 2 aggregate interface view:interface bridge-aggregationinterface-number• Enter Layer 3 aggregate interface view:interface route-aggregationinterface-numberN/A3. Enable BFD for theaggregationgroup.link-aggregation bfd ipv4 source ip-addressdestination ip-addressBy default, BFD is disabled for anaggregation group.Shutting down an aggregate interfaceMake sure no member port in an aggregation group is configured with the loopback command whenyou shut down the aggregate interface. Similarly, a port configured with the loopback command cannotbe assigned to an aggregate interface already shut down. For more information about the loopbackcommand, see Layer 2—LAN Switching Command Reference.Shutting down or bringing up an aggregate interface affects the aggregation state and link state of portsin the corresponding aggregation group in the following ways:• When an aggregate interface is shut down, all Selected ports in the corresponding aggregationgroup become Unselected and their link state becomes down.• When an aggregate interface is brought up, the aggregation state of ports in the correspondingaggregation group is recalculated.To shut down an aggregate interface:Step Command1. Enter system view. system-view2. Enter aggregate interface view.• Enter Layer 2 aggregate interface view:interface bridge-aggregation interface-number• Enter Layer 3 aggregate interface or subinterface view:interface route-aggregation { interface-number |interface-number.subnumber }3. Shut down the aggregate interface. shutdown
