By certskills May 30, 2016 09:05


#CDP has long been the default and favored protocol for a variety of device discovery functions, but LLDP offers an alternative as well. (LLDP is new to the exam topics per the May 2016 new CCENT and CCNA R&S exams.) Both are supported in Cisco routers and switches, with similar configuration. This lab asks you to work through the commands to enable and disable both CDP and LLDP for the sake of exercising your CLI config skills with these protocols.


Configure CDP and LLDP in the topology shown in the figure. In particular, use CDP only in the top part of the topology, and LLDP only in the bottom part. The specific rules for this lab are:

  • Use only CDP on the R1 and R2 G0/2 interfaces
  • Use only LLDP on the R1 and R2 G0/1 interfaces
  • Use only CDP on switch SW1
  • Use only LLDP on switch SW2, R4, and R4
  • Assume all device interfaces shown in the lab are up and working

Figure 1: Device Discovery Topology

Initial Configuration

Examples 1 through 6 show the beginning configuration state of the four routers and the two switches.

Example 1: R1 Config


Example 2: R2 Config


Example 3: R3 Config


Example 4: R4 Config


Example 5: SW1 Config


Example 6: SW2 Config


Answer on Paper, or Maybe Test in Lab

Next, write your answer on paper. Or if you have some real gear or other tools, configure the lab using them.

To test your solution if you happen to try it with VIRL or real gear, you can check by going to any of the routers and displaying the LLDP neighbors or by going to R1 or R2 and displaying the CDP neighbors. Use commands like show cdp neighbors, show lldp neighbors, show cdp interfaces, and show lldp interfaces. For instance, R1 should see SW1 as a neighbor with CDP, and SW2 as a neighbor with LLDP. SW2 should see R1, R2, R3, and R4 as a neighbor with LLDP.


Do this Lab with Cisco’s VIRL

You can do these labs on paper and still get a lot out of the lab. As an extra help, we have added files for the Virtual Internet Routing Lab (VIRL) software as well. The .VIRL file found here is a file that when used with VIRL will load a lab topology similar to this lab’s topology, with the initial configuration shown in the lab as well. This section lists any differences between the lab exercise and the .VIRL file’s topology and configuration.

Download this lab’s VIRL file!

The virl topology matches this lab topology exactly. The host info does as well.

Answers: RIPv2 Basics 1
Answers: CDP/LLDP 1
By certskills May 30, 2016 09:05
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  1. abrakour July 19, 16:00

    Hi Wendell,

    I didn’t know where to post this question, so this is the most relevant place I could find (sorry).

    The question is about something mentioned in the book, that I cannot cross-reference with my equipment (don’t have any) and it contradicts with all the examples on the book and my labs using PT.

    In chapter 33, page 793, “Key Topic”, “Address List: Network and data link addresses”. The book here states that CDP supports providing the IP, as well as the MAC address of the remote interface but (!).
    There is no example, using CDP, that any MAC address appears. I tried all show commands with PT too and no MAC is shown. Later on LLDP the MAC address, or “Chassis id” as mentioned there, is shown (page 798).

    So my question is: Does CDP really shows MAC addresses or is there a “typo” in p.793?

    Thank you for your time,

    Reply to this comment
    • CCENTSkills July 21, 09:53

      Hi Abrakour,
      First, for process, all the Cisco Press books have a “Feedback” or similar heading on page iii that describe how to get in touch with them/us about any Cisco Press product for product support. I do attempt to keep that process separate from this blog space, although I think it’s perfectly normal for people to think to come here for product support, so no worries. But I do tend to make sure and clear the outstanding errata queries that occur through the formal channel before looking at items here in the blog, just to be fair to those that find and follow that channel.

      That said, I’ll do a separate reply here in just a bit on the technology part of your post.

      Reply to this comment
  2. RN December 14, 16:59

    Hello Wendell,

    CTRL-F this line:

    Use only LLDP on switch SW2, R2, and R3

    Shouldn’t R4 also be included?



    Reply to this comment
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