Probe-based failure detection uses target systems to determine the condition of an interface. Each target system must be attached to the same IP link as the members of the IPMP group. The in.mpathd daemon on the local system sends ICMP probe messages to each target system. The probe messages help to determine the health of each interface in the IPMP group.
For more information about target system use in probe-based failure detection, refer to Probe-Based Failure Detection.