Cisco Discovery Protocol (CDP)

CDP is a Cisco p proprietary data link layer protocol developed by Cisco Systems. It is used by Cisco devices to discover and learn about neighboring Cisco devices directly connected to them. CDP can provide information such as the operating system version, IPv4 or IPv6 address, device capabilities, and more. This can be useful for network management and troubleshooting.

https://networklessons.com/cisco/ccie-enterprise-infrastructure/introduction-to-cdp-cisco-discovery-protocol