Cisco DiscoveryProtocol:
• The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer protocol developed by Cisco Systems.
• It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address.
• By default, CDP announcements are sent every 60 seconds on interfaces
• Each Cisco device that supports CDP stores the information received from other devices in a table that can be viewed using the show cdp neighbors command.
• From a troubleshooting perspective, CDP can be used to either confirm or fix the documentation shown in a network diagram, or even discover the devices and interfaces used in a network.
• The show cdp neighbor command delivers information about directly connected devices
