42 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 4 Copyright © 2004, Cisco Systems, Inc.
4.1.3 Implementation, monitoring, and maintenance of CDP
CDP implemented by default on all interfaces that support it. The following table lists variations
of the CDP command and their functions. These commands should be used in privileged
EXEC mode. The table is located in this section of the curriculum.
Although not noted in the curriculum, many of these commands can be executed in user
mode. Some of the configuration commands are done in global configuration mode and some
require interface configuration mode.
Discuss the cdp enable and cdp run commands. The cdp enable command is an
interface configuration command that enables CDP on a particular interface. The cdp run
command is a global configuration command that enables CDP on a Cisco device. Students
should also be comfortable with the no form of these commands. Relevant TIs from CCNA 2
v2.1.4 are 4.3.3 and 4.3.4.
Demonstrate command usage after the class reviews the table.
Command Purpose
cdp enable Enables CDP on an interface
cdp advertise-v2 Enables CDP Version-2 on an interface
clear cdp counters Resets the traffic counters to zero
show cdp Displays the interval between transmissions of
CDP advertisements, the number of seconds the
CDP advertisement is valid for a given port, and
the version of the advertisement
show cdp entry entry-name
[protocol | version] Displays information about a specific neighbor,
which can be limited to protocol or version
information
show cdp interface [type
number] Displays information about interfaces on which
CDP is enabled
show cdp neighbors [type
number] [detail] Displays the type of device that has been
discovered, the name of the device, the number
and type of the local interface or port, the number
of seconds the CDP advertisement is valid for the
port, the device type, the device product number,
and the port ID
Displays information on the native VAN ID, the
duplex mode, and the VTP domain name
associated with neighbor devices when the
detail keyword is used
4.1.4 Creating a network map of the environment
CDP uses advertisements to collect information about its neighbors. Its limitation is that it only
collects information from directly-connected devices. The telnet command can be used in
conjunction with cdp commands to create a network map. To do this, a network administrator
can console into one router and use the telnet command to move from router to router.