The service attempts to communicate with network devices via the SNMPv2c protocol. If a device fails to respond to the SNMPv2c queries, the service will attempt to communicate via SNMPv1.
By default, the service will try three times to communicate with the device, waiting 3 seconds between each try. Thus, it can take 9 seconds for the device to fail to respond to SNMPv2c packets before an SNMPv1 packet is sent.
If there are a lot of devices on the network that only support SNMPv1, the service will have to wait 9 seconds for each device to fail before it is able successfully communicate with the device.
Workaround: It is recommended that all monitored network devices are upgraded to the latest release of code so they can support SNMPv2c.