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CDP & LLDP Questions

November 22nd, 2017 Go to comments

Question 1


CDP is enabled by default on all Cisco routers. If it is turned off by any reason, we can turn it on again with the following command on global configuration mode:

Router(config)#cdp run

Note: CDP can be turned on or turned off on each interface. For example to turn off CDP on an interface we use this command:

Router(config-if)#no cdp enable

Question 2


Link Layer Discovery Protocol (LLDP) is a industry standard protocol that allows devices to advertise, and discover connected devices, and there capabilities (same as CDP of Cisco). To enable it on Cisco devices, we have to use this command under global configuration mode:

Sw(config)# lldp run

Question 3


The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer protocol (Layer 2 protocol) developed by Cisco. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address. The most popular command with CDP is “show cdp neighbors” to discover who is the neighbors.


There are 3 columns we should pay more attention to:

+ Local Interface (Local Intrfce): the interfaces on the device you are using “show cdp neighbors” command. In this case it is the interface of HOME router
+ Platform: the platform of neighbor device

+ Port ID: the neighbor device’s port or interface on which the CDP packets are multicast

Question 4


Only the “show cdp neighbor detail” gives us information about the IP address of the connected device. Below is an example of this command.


Question 5

Question 6

Question 7

Comments (9) Comments
  1. hah
    February 8th, 2017

    where is the question for this?

  2. Anonymous
    February 23rd, 2017

    where is the question .. i just find the answer !!!!!!!!!!

  3. Mr. Ro
    February 23rd, 2017

    Try to check the follow link:
    There, You’ll find the question.

  4. Neil
    February 27th, 2017

    CDP runs on?

    a) Native VLAN)
    b) VLAN 1?

  5. Anonymous
    March 28th, 2017

    hey people we must go through the questions first before you start reading answers its inconveniencing for some to be asking for questions kind regards Cyber Pandor

  6. ss
    March 29th, 2017


  7. Delta.Rar
    April 28th, 2017

    It is more profitable to get more understanding on each tutorial of the Cisco course and in that way it gets easy to relate questions and answers with much more feel to it; yet again it makes you not to be left behind.

  8. rajput……..
    May 14th, 2017

    cdp runs on ?

  9. @neil
    July 8th, 2017

    All CDP packets include a VLAN ID. If you configure CDP on a Layer 2 access port, the CDP packets sent from that access port include the access port VLAN ID. If you configure CDP on a Layer 2 trunk port, the CDP packets sent from that trunk port include the lowest configured VLAN ID allowed on that trunk port. The trunk port can receive CDP packets that include any VLAN ID in the allowed VLAN list for that trunk port.


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