Implementation, monitoring, and maintenance of CDP / Creating a network map of the environment

Implementation, monitoring, and maintenance of CDP

4.1.3 This page will introduce the commands that are used to implement, monitor, and maintain CDP information: 

• cdp run
• cdp enable
• show cdp traffic
• clear cdp counters
• show cdp
• show cdp entry {*|device-name [*][protocol | version]}
• show cdp interface [type number]
• show cdp neighbors [type number] [detail]

The cdp run command is used to enable CDP globally on a router. By default, CDP is globally enabled. The cdp enable command is used to enable CDP on a particular interface. On Cisco IOS Release 10.3 or higher, CDP is enabled by default on all supported interfaces to send and receive CDP information. CDP can be enabled on all device interfaces with the cdp enable command.
The Lab Activity on this page will teach students about some basic CDP commands.
The next page will explain how CDP can be used to create a network map. 

Creating a network map of the environment

4.1.4

This page will explain how the information that is obtained by CDP can be used to create a network map.

CDP was designed and implemented as a simple, low-overhead protocol. Though a CDP frame can be small, it can retrieve a lot of useful information about directly connected Cisco devices.

This information can be used to create a network map of the connected devices. To discover devices that are connected to neighbor devices, use Telnet to connect to the neighbors. Then use the show cdp neighbors command.

The Lab Activity will show students how to use CDP commands to learn about neighboring network devices.

The next page will describe how CDP can be disabled.