2.1.b Implement and troubleshoot layer 2 protocols

2.1.b [i] CDP, LLDP

Cisco Discovery Protocol (CDP) is a Cisco proprietary data link layer protocol. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address.

Link Layer Discovery Protocol (LLDP) is a vendor-neutral link layer protocol developed by IEEE . It is used by network devices for advertising their identity, capabilities, and neighbors on a local area network, principally wired Ethernet.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 1527-1529).  . Kindle Edition.

http://en.wikipedia.org/wiki/Cisco_Discovery_Protocol