Configuring for Network Management Applications

CDP

CDP-disabled switch) does not forward CDP packets; i.e. is not transparent to CDP traffic. (For the same reason, switch “E” does not have any CDP neighbors.)

Figure 13-12 (page 13-29)illustrates how multiple CDP neighbors can appear on a single port. In this case, switch “A” has three CDP neighbors on port 1 because the intervening devices are not CDP-capable and simply forward CDP neighbors data out all ports (except the port on which the data was received).

Default Configuration. In the factory-default configuration, CDP is enabled and running on all ports. In this case, the holdtime is 180 seconds and the timer (CDP Transmit Interval) is 60 seconds.

Configuring CDP on the Switch

Using CDP you can:

View the switch’s current global and per-port CDP configuration

List the current contents of the switch’s CDP Neighbors table (that is, view a listing of the CDP devices of which the switch is aware)

Enable or disable CDP (Default: Enabled)

Specify the hold time (CDP packet time-to-live) for CDP data deliv­ ered to neighboring CDP devices. For example, in CDP switch "A" you can specify the hold time for switch "A" entries in the CDP Neighbor tables of other CDP devices. (Default: 180 seconds)

Specify the transmission interval for CDP packets. (Default: 60 seconds)

CLI: Viewing and Configuring CDP

CDP Commands

Page

 

 

show CDP

13-32

show CDP neighbors

13-32

cdp clear

13-33

[no] cdp run

13-34

[no] cdp enable

13-35

cdp holdtime

13-36

cdp timer

13-36

 

 

13-31