About Discovery
The Discovery feature scans the devices in your network and sends the list of discovered devices to Inventory.
The Discovery 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.
There are three ways for you to discover devices:
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Use Cisco Discovery Protocol (CDP) and provide a seed IP address.
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Specify a range of IP addresses. (A maximum range of 4096 devices is supported.)
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Use Link Layer Discovery Protocol (LLDP) and provide a seed IP address.
When configuring the Discovery criteria, remember that there are settings that you can use to help reduce the amount of time it takes to discover your network:
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CDP Level and LLDP Level: If you use CDP or LLDP as the Discovery method, you can set the CDP or LLDP level to indicate the number of hops from the seed device that you want to scan. The default, level 16, might take a long time on a large network. So, if fewer devices have to be discovered, you can set the level to a lower value.
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Subnet Filters: If you use an IP address range, you can specify devices in specific IP subnets for Discovery to ignore.
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Preferred Management IP: Whether you use CDP, LLDP, or an IP address range, you can specify whether you want Cisco DNA Center to add any of the device's IP addresses or only the device's loopback address.
Note
For Cisco SD-Access Fabric and Cisco DNA Assurance, we recommend that you specify the device's loopback address.
Regardless of the method you use, you must be able to reach the device from Cisco DNA Center and configure specific credentials and protocols in Cisco DNA Center to discover your devices. These credentials can be configured and saved in the window or on a per-job basis in the Discovery window.
![]() Note |
If a device uses a first hop resolution protocol like Hot Standby Router Protocol (HSRP) or Virtual Router Redundancy Protocol (VRRP), the device might be discovered and added to the inventory with its floating IP address. Later, if HSRP or VRRP fails, the IP address might be reassigned to a different device. This situation can cause issues with the data that Cisco DNA Center retrieves for analysis. |