Calling sequence for SNMP sensors

The calling sequence for SNMP sensors is dependent on which sensors are enabled in the discovery profile and on what data is discovered.

In Level 1 discovery profiles, use the SNMP Light sensor with the Stack Scan sensor to improve the accuracy of the discovery. In Level 2 or Level 3 discovery profiles, use the SNMP MIB2 sensor, which discovers additional data for building detailed Level 2 topologies.

Figure 1 illustrates the calling sequence for the SNMP Light sensor and the SNMP MIB2 sensor.

The ping sensor calls the port sensor.

If the SNMP Light sensor is enabled, the port sensor calls the SNMP Light sensor. If the port sensor discovers WMI or SSH ports and if the session sensor is enabled, the port sensor launches the session sensor. If the port sensor does not discover WMI or SSH ports or if the session sensor cannot establish a connection to the remote host, the port sensor calls the SNMP MIB2 sensor.

Figure 2 illustrates the calling sequence for SNMP sensors, starting after the SNMP Light sensor or the SNMP MIB2 sensor is called.

Depending on the data that the SNMP Light sensor or the SNMP MIB2 sensor discovers from the devices, the following sensors are called:

If a Cisco device is discovered, the Cisco port sensor and the Cisco VLAN sensor are called.
If a Fibre Channel switch is discovered, the Fibre Channel switch sensor is called.
If no Fibre Channel switch is discovered, the Entity MIB sensor and the Bridge SNMP sensor are called. However, these sensors must be enabled in the discovery profile.
If the discovered device matches a custom MIB computer system template, the Custom MIB2 computer system sensor is called.

Figure 1. Calling sequence for SNMP Light sensor and SNMP MIB2 sensor

Figure 2. Calling sequence for SNMP sensors, starting after the SNMP Light sensor or the SNMP MIB2 sensor is called