Neighbour Discovery Protocols – Part 4 (CDP Configuration with Packet Tracer)

CDP Packet Tracer Example

Packet Tracer CDP Configuration

As we have talked about in the previous lesson, CDP is a Cisco proprietary protocol. In this article, we will discuss how to configure CDP in Cisco IOS, we will learn CDP Cisco Configuration. LLDP is a standard neighbour discovery protocol. In another lesson we will also configure LLDP.

You can DOWNLOAD the Packet Tracer example with .pkt format HERE.

For all Packet Tracer Examples and Files, you can check Packet Tracer Labs Page.

For our example, the below topology is used.

CDP Configuration Topology

CDP Configuration Topology
Above, there is a L2 swith, a L3 switch, a router, an IP Phone and a PC are connected to the central switch.

We will not talk about the configuration of the central switch, but we will talk about the general CDP configuration commands.

To enable CDP globally, use “cdp run” on the router configuration mode.

Switch(config)# cdp run

To enable CDP on a specific interface, use “cdp enable” command on the interface configuration mode.By default CDP is already enabled. You can also disable CDP by using “no cdp enable” command.

Switch(config-if)# cdp enable
Switch(config-if)# no cdp enable

To configure cdp hello time and hold time, you can use the below commands. Time is mentioned as seconds.

Switch(config)# cdp timer 50
Switch(config)# cdp holdtime 100

To clear the CDP table, use the “clear cdp table” command.

Switch# clear cdp table

To verify CDP, you can use general CDP verification commands below:

Switch# show cdp
Switch# show cdp interface
Switch# show cdp neighbors
Switch# show cdp entry
Switch# show cdp traffic

In our topology, for the central switch, “show cdp neighbours” and “show cdp interface” command outputs are showed below.

Switch>show cdp neighbors 
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID    Local Intrfce   Holdtme    Capability   Platform    Port ID
IP Phone     Fas 0/4          124            H P     7960         
Switch       Fas 0/6          124                    3560        Fas 0/1
Switch       Fas 0/2          124            S       2960        Fas 0/2
Router       Fas 0/5          124            R       C2800       Fas 0/0
Switch       Fas 0/1          124            S       2950        Fas 0/1

For all Packet Tracer Examples and Files, you can check Packet Tracer Labs Page.

One Response to “Neighbour Discovery Protocols – Part 4 (CDP Configuration with Packet Tracer)”

  • Antony Maraka / Reply

    There is nothing more good than waking up very early and sleeping very late in the night going through the Tutorials found on this site.
    Eng Gokhan, you are a blessing to me brother.

    Maraka in Nairobi, Kenya

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