This statement is false . In an Eth-Trunk operating in LACP mode , if the administrator sets the maximum number of active links to 3 and there is 1 standby link, then when one active member fails, LACP can automatically promote the standby member to active status. The purpose of the standby member is to maintain the configured active-link capacity whenever possible.

Therefore, after one active link fails, the normal expectation is not that the active-link count is reduced from 3 to 2 while the standby link remains idle. Instead, the standby link should participate and replace the failed member, so that the Eth-Trunk continues operating with 3 active links if the standby link and negotiation conditions are normal. This reflects the redundancy and fast recovery capabilities of LACP-based aggregation. HCIA-Datacom highlights that compared with manual mode, LACP provides more intelligent link selection, active/standby management, and fault adaptation. The statement is wrong because it ignores the intended behavior of the standby link in maintaining the number of active forwarding links after a failure.