The Inventory function retrieves and saves details, such as host IP addresses, MAC addresses, and network attachment points about devices in its database.
The Inventory feature can also work with the Device Controllability feature to configure the required network settings on devices, if these settings are not already present on the device. For more information about Device Controllability, see the Cisco DNA Center Administrator Guide.
Inventory uses the following protocols, as required:
Link Layer Discovery Protocol (LLDP).
IP Device Tracking (IPDT) or Switch Integrated Security Features (SISF). (IPDT or SISF must be enabled on the device.)
LLDP Media End-point Discovery. (This protocol is used to discover IP phones and some servers.)
Network Configuration Protocol (NETCONF). For a list of devices, see Discovery Prerequisites.
After the initial discovery, Cisco DNA Center maintains the inventory by polling the devices at regular intervals. The default interval is every 6 hours. However, you can change this interval upto 24 hours, as required for your network environment. For more information, see Update Device Resync Interval. Also, a configuration change in the device triggers an SNMP trap, which in turn triggeres device resynchronisation. Polling occurs for each device, link, host, and interface. Only the devices that have been active for less than a day are displayed. This prevents stale device data, if any, from being displayed. On an average, polling 500 devices takes approximately 20 minutes.