Home > CDP & LLDP Questions

CDP & LLDP Questions

November 22nd, 2017 Go to comments

Question 1

Explanation

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

Explanation

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

Explanation

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.

show_cdp_neighbors3.jpg

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

Explanation

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

ccna_vtp_sim_answer_4_show_cdp_neighbors_detail.jpg

Question 5

Question 6

Question 7

Question 8

Question 9

Explanation

Type Length Values (TLVs) are blocks of information embedded in CDP advertisements which gives details like IP address, device-id, platform…

Comments (12) 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:
    http://juquitiba.sp.gov.br/?exams=ccna-faqs-a-tips
    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

    hellooo

  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 ?
    ans:-vlan1

  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.

    http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/system_management/configuration/guide/sm_nx_os_cg/sm_4cdp.html

  10. NotAexpert
    June 29th, 2018

    Which statement about LLDP is true?
    A. It is a Cisco proprietary protocol.
    B. It is configured in global configuration mode.
    C. The LLDP update frequency is a fixed value.
    D. It runs over the transport layer.

    B is true, but also C, because

    lldp timer seconds

    Example:
    switch(config)# lldp timer 50
    (Optional) Specifies the transmission frequency of LLDP updates in seconds.
    The range is 5 to 254 seconds; the default is 30 seconds.

  11. NotAexpert
    June 29th, 2018

    I am sorry, of course the value is variable.

  12. zamil
    November 2nd, 2018

    Q 7

    LLDP supports a set of attributes that it uses to discover neighbor devices. These attributes contain type, length, and value descriptions and are referred to as TLVs. LLDP supported devices can use TLVs to receive and send information to their neighbors. This protocol can advertise details such as configuration information, device capabilities, and device identity.
    The switch supports these basic management TLVs. These are mandatory LLDP TLVs.
    + Port description TLV
    + System name TLV
    + System description TLV
    + System capabilities TLV
    + Management address TLV
    These organizationally specific LLDP TLVs are also advertised to support LLDP-MED.
    + Port VLAN ID TLV ((IEEE 802.1 organizationally specific TLVs)
    + MAC/PHY configuration/status TLV(IEEE 802.3 organizationally specific TLVs)

    -> No VTP information is supported in LLDP.

Add a Comment