Cisco Discovery Protocol and Link-Layer Discovery Protocol overview

It is apparent that both the Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP) operate on OSI Layer 2 and have to do with discovering neighbor devices. However, CDP is a Cisco proprietary protocol, while LLDP is a vendor-neutral protocol. In addition, CDP is enabled by default on Cisco devices, where as LLDP is required to be enabled. This section describes how to configure both CDP and LLDP on Cisco switches.

Device discovery with CDP

Obviously, since it is developed by Cisco, CDP runs on all Cisco devices. CDP periodically sends advertisements out of all ports to connected devices. These advertisements contain information, such as the...