Cisco Discovery Protocol (proprietary) runs only on Cisco devices; it allows you to gather information about other routers and switches. It is enabled by default. It can also be a very useful command to use while troubleshooting to see which devices are directly connected to the device you are connected to.
To disable CDP For the whole switch:
Router(config)#no cdp run
To disable CDP for an interface:
Router(config-if)#no cdp enable
show cdp show cdp neighbors show cdp neighbors detail show cdp entry
Open source CDP = LLDP
To support non-Cisco devices and to allow for interoperability between other devices, the switch supports the IEEE 802.1AB LLDP. LLDP is a neighbor discovery protocol that is used for network devices to advertise information about themselves to other devices on the network. This protocol runs over the data-link layer, which allows two systems running different network layer protocols to learn about each other.
LLDP supports a set of attributes that it uses to discover neighbor devices. These attributes contain type, length, and value descriptions and are referred to as TLVs. LLDP supported devices can use TLVs to receive and send information to their neighbors. Details such as configuration information, device capabilities, and device identity can be advertised using this protocol.
LLDP is disabled by default
To Enable LLDP globally:
config t lldp run end
To Enable LLDP per interface:
config t int fa0/0 lldp transmit lldp receive end copy run start
clear lldp counters clear lldp table show lldp show lldp errors