Before sending an SNMP request, the discovery process sends an ICMP poll to the system to ensure it is reachable. The defaultICMPAutoRetries and defaultICMPAutoTimeout control the ICMP poll that is used during the initial stage of discovery.
Retries is the number of times an ICMP poll is sent to a system after the initial attempt fails. The default value is 3. Timeout is the amount of time that should elapse before considering that the previous ICMP poll has failed or timed out. The default value is 500 milliseconds.
The value of the timeout is constant, meaning that the value stays the same between retries. In contrast, the value of the timeout for the SNMP poller doubles after each retry.