Cisco Discovery Protocol (CDP) It seems simple enough, but there are certainly some details to know for success on the CCNA. In your CCNP study, we introduce additional applications for CDP, but for now just know that CDP is designed, is to provide information about directly connected Cisco routers and switches.
CDP by default between all directly connected Cisco devices. CDP is a Cisco proprietary protocol - ifthe device is directly connected to a Cisco device, you will not have the desired information.
Command CDP is to provide basic information about directly connected neighbors display "show CDP neighbor.
R2 # show cdp neighbor
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
ID of the local device INTRFCE Holdtme Capability Platform Port ID
R1 BRI0167 R 2521 Dialer1
This command is especially useful when troubleshooting Cisco switches. There is no need to see the wiring in a rack of Cisco equipment to track what needs to be changed to a Cisco router when the next show cdp can be used together. In the above output, you can be the remote device the hostname, which is connected to the interface of the remote device to see, with the local device, the ability of the remote device, the remoteHardware platform of the device and the local interface is connected to the remote device.
CDP can be disabled globally and the interface. To disable CDP at the interface, which allows run no cdp enable CDP on the interface and make it again.
CDP CDP timer determines how often transmitted packets, and CDP holdtime defines how long a device will be in possession of a received packet.
To turn off CDP for entire router, do not run CDP. To see the current globalThe state of the race show cdp CDP.
R2 # show cdp
Global CDP information:
Sending CDP packets every 60 seconds
Send a hold time value of 180 seconds
CDP runs by default.
R2 # conf t
R2 (config) # cdp timer 45
R2 (config) # cdp holdtime 100
The CDP timer to be changed.
R2 # show cdp
Global CDP information:
Sending CDP packets every 45 seconds
Send a standby time of 100 seconds
CDP values have been successfullychanged. "The show cdp interface is" the timer information for each interface of the router.
R2 # conf t
R2 (config) # interface BRI0
R2 (config-if) # no cdp enable
CDP is disabled BRI. This is not done to hold the line to make outgoing calls.
R2 # conf t
R2 (config) # no cdp run
CDP is globally disabled.
R2 # show cdp
% CDP is not enabled
CDP has been successfully disabled.
Show cdp neighbor offers a rangeinformation, but if the IP address of your neighbor? Simply show CDP neighbor detail. Receive more information about directly connected neighbors, including your IP address.
SW2 # show cdp neighbor detail
-------------------------
Device ID: R4
Entry address (es):
IP Address: 172.12.23.4
Platform: Cisco 2520, Capabilities: Router
Interface: FastEthernet0 / 4, Port ID (outgoing port): Ethernet0
Hold Time: 158sec
The details of the CDP are important to you in the labor market and in the CCNA exam room. If you are negotiating a poorly documented network, you can create CDP "walk" through the network and a network for your customers as well. Sometimes the simplest protocols are the most useful!