Cisco Discovery Protocol
The Cisco Discovery Protocol (CDP) was developed by Cisco Systems. It's primarily used to obtain the protocol addresses of neighboring devices and also to discover the platform of those devices. It can also be used to show information about the interfaces your router uses. CDP is media and protocol-independent, and runs on all Cisco-manufactured equipment including routers, bridges, access servers, and switches. CDP runs only over the data link layer enabling two systems that support different network-layer protocols to learn about each other. CDP Version-2 (CDPv2) is the most recent release of the protocol and provides more intelligent device tracking features.