Discovery error scenarios and results

Discovery error scenarios and resultsdescribes different discovery error scenarios and results. Initial discovery refers to an attempt to discover a system that has not been previously discovered, and thus is not in the modeled topology. Rediscovery refers to an attempt to discover a system that is already in the topology.

Table 1. Discovery error scenarios and results

Discovery or rediscovery	Condition	Result
Discovery (initial discovery)	Cannot resolve hostname to IP address.	Add system to Pending Devices list. System hostname does not resolve to an IP address provides more information.
	No response from ICMP ping.	For a seed system (manual discovery), add system to the Pending Devices list as UNDISCOVERED. For a system that is found through autodiscovery, discard system.
	No response from SNMP agent.	For a seed system (manual discovery), add the system to the Pending Devices list as UNDISCOVERED. For a system that is found through autodiscovery, and ShowPendingNONSNMP set to TRUE, add the system to the Pending Devices list as UNDISCOVERED. For a system that is found through autodiscovery, and ShowPendingNONSNMP set to FALSE, discard the system. System does not support SNMP provides more information.
	ICMP response and SNMP response; current system limit exceeded.	For a seed system (manual discovery) or a system that is found through autodiscovery, display System limit exceeded message in the Discovery Progress window and add the system to the Pending Devices list as UNDISCOVERED.
	ICMP response and SNMP response; manual accept mode enabled for discovery filter.	For a system that matches the discovery filter, add the system to the Pending Devices list as THROTTLED.
	Insufficient number of volume licenses, which prevents complete discovery of systems.	Stop discovery process and send an OutOfLicense notification. Show “Out of license” message in the Discovery Progress window. Add any new discovery candidate systems to the Pending Devices list as UNDISCOVERED.
	Discovery completes successfully.	Classify system in accordance to its sysObjectID and add to topology. If the OID is not recognized, classify system as a Node.
Rediscovery	Receive no response from SNMP agent: SNMP request times out.	Send notification, typically Agent NotResponding, which is based on the correlation analysis, and send a DiscoveryError notification.
	SNMP agent encounters a loop, which prevents the system from being discovered.	Classify system according to its sysObjectID, add to topology, and send a DiscoveryError notification.
	No response from ICMP ping.	Send notification, typically Down, and send a DiscoveryError notification.
	Discovery not able to contact SNMP agent at known address.	Send a DiscoveryError notification.
	SNMP agent fails authentication.	Send a DiscoveryError notification.