User's Manual

17-2

Cisco IOS Software Configuration Guide for Cisco Aironet Access Points

OL-11350-01

Chapter 17 Configuring CDP

Understanding CDP

Cisco Discovery Protocol (CDP) is a device-discovery protocol that runs on all Cisco network

equipment. Each device sends identifying messages to a multicast address, and each device monitors the

messages sent by other devices. Information in CDP packets is used in network management software

such as CiscoWorks2000.

CDP is enabled on the access point Ethernet port by default. However, CDP is enabled on the access

point radio port only when the radio is associated to another wireless infrastructure device, such as an

access point or a bridge. CDP is sent on the lowest VLAN number configured on the access point. When

more than on VLAN is used in a wireless network, Cisco recommends that the lowest VLAN number

configured be used as the native VLAN

Note For best performance on your wireless LAN, disable CDP on all radio interfaces and on sub-interfaces

if VLANs are enabled on the access point.

Configuring CDP

This section contains CDP configuration information and procedures:

• Default CDP Configuration, page 17-2

• Configuring the CDP Characteristics, page 17-2

• Disabling and Enabling CDP, page 17-3

• Disabling and Enabling CDP on an Interface, page 17-4

Default CDP Configuration

Table 17-1 lists the default CDP settings.

Configuring the CDP Characteristics

You can configure the CDP holdtime (the number of seconds before the access point discards CDP

packets) and the CDP timer (the number of seconds between each CDP packets the access point sends).

Beginning in Privileged Exec mode, follow these steps to configure the CDP holdtime and CDP timer.

Table 17-1 Default CDP Configuration

Feature Default Setting

CDP global state Enabled

CDP interface state Enabled

CDP holdtime (packet holdtime in seconds) 180

CDP timer (packets sent every x seconds) 60