IPv6 EUI-64 Addressing 1

certskills
By certskills July 21, 2016 09:05

Do you know how to take an interface MAC address and determine what IPv6 address the interface would use when using EUI-64? Could you then do the reverse: take the IPv6 address, and predict what MAC address is used for the interface? This latest lab asks you to configure IPv6 addresses, but with a twist: use modified EUI-64, but starting with a desired IPv6 address. Your job: calculate the prefix and MAC address that you need so that the router chooses the IPv6 addresses requested in the lab.

Requirements

Routers can be configured with full IPv6 unicast addresses on their interfaces, but they can also be configured using the modified EUI-64 address assignment feature. With this feature, the router creates the EUI-64 value by taking the interface MAC address (48 bits, or 12 hex digits), inverts the 7th bit, and inserts hex FFFE into the middle. Then it combines the 64-bit prefix configured on the ipv6 address interface subcommand, with this EUI-64 calculated 64-bit value, to create the interface IPv6 address.

In this lab, configure all router interfaces using the modified EUI-64 feature to create the IPv6 addresses listed in the table. The specific rules for this lab are:

  • Use EUI-64 addressing on all router interfaces.
  • Use the mac-address command to configure each interface’s MAC address, so that the resulting IPv6 address will match table 1.
  • Assume all router interfaces shown in the lab are up and working.

 

Table 1 – Final IPv6 Address Assignments

Device Interface IPv6 Address
R1

GigabitEthernet0/1

2000::12FF:FE34:5678
R1 GigabitEthernet0/2 2001:BAE:274F:BAED:AE13:72FF:FE94:6256
R2 GigabitEthernet0/1 2000::C281:ABFF:FEED:C724
R2 GigabitEthernet0/2 2001:BA82:B0AE:CAE:7A24:FBFF:FECE:A103
R3 GigabitEthernet0/1 2000::214:ABFF:FEC2:8ABE
R3 GigabitEthernet0/2 2001:BA81:8326:2753:AE13:FEFF:FEDA:BECA
R4 GigabitEthernet0/1 2000::AEED:ABFF:FEEC:FDAC
R4 GigabitEthernet0/2 2001:BEDE:AB81:9173:9A76:12FF:FE34:7654

 

 

Figure 1: EUI-64 IPv6 Addressing Topology

Initial Configuration

Examples 1, 2, 3, and 4 show the beginning configuration state of R1, R2, R3, and R4.

Example 1: R1 Config

Example 2: R2 Config

Example 3: R3 Config

Example 4: R4 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 verify it by going to each of the routers and verifying the address calculated by the device when it uses EUI-64; this can be done with the show ipv6 interface or show ipv6 interface brief commands.

 

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

Answers: PPP over Ethernet 2
GRE Tunnel 3
certskills
By certskills July 21, 2016 09:05
Write a comment

6 Comments

  1. Mansoor May 14, 13:42

    Dear Mr. Wendall,

    In your ICND1 book for Chapter 30 Appendix K, practice problems, I have noticed the answers to solicited node multicast address is shown as FF02::01:FF… for all answers.

    Can the above answers be written as FF02::1:FF… thats how I got the answers following the abbreviation rules. Please advise if my answer is correct or is there some errata in Appendix K.

    Studying for CCNA. 🙂

    Thanks a lot.

    Reply to this comment
    • CCENTSkills May 16, 09:03

      Hi Mansoor,
      I think I am not quite understanding your question, but let me make an attempt at an answer.

      This exercise does not ask for any solicited node multicast addresses. If it had, they would indeed all begin with FF02::1:FF… However, given that this exercise references unicast addresses only, none of those would begin with FF. So the literal answer to your question is no, you can’t list the answers as beginning with FF02… etc . Which makes me think I’m totally missing your point. 🙂
      Feel free to follow up.
      Wendell

      Reply to this comment
  2. Mansoor May 21, 12:58

    Hi Wendall,

    Just saw this now. In Appendix K you have mentioned ‘Also in table K-2 list the solicited node address. If you see the answers in Table K-3 ‘Answers to Problems in Table K-1
    we see here column 2 mentions the Soclicited Node Multicast Address results… that is where my confusion is all answers are shown as FF02::01… Here I want to know if we can write the answers as FF02::1. As per the abbreviation rules. 🙂

    Hope I’m clear here.

    Reply to this comment
    • CCENTSkills May 24, 07:55

      Hi Mansoor,
      I still may not understand you, but let me attempt an answer.
      This lab says nothing about solicited node multicasts.
      If you wanted to also calculated the solicited node multicasts, as is requested in that exercise in the book’s appendix K… then yes, all the solicited node multicasts would begin FF02::1, just as you said.
      Is that what you’re getting at?

      Reply to this comment
      • Mansoor May 24, 12:34

        Yes Mr. Wendall,

        Yes that is the point I needed clarification.

        I will assume its a typo then. 🙂

        It still beats me why the 10 or so Answers all have the typos. Anyways thank you.
        Thanks.

        Reply to this comment
  3. Matt February 21, 06:27

    Dear Mr. Wendell,

    I just want to say thank you for this exercise, it has really spinned my brain 🙂

    Keep up the good work!

    Thank you!

    Matt

    Reply to this comment
View comments

Write a comment

Comment; Identify w/ Social Media or Email

Subscribe

Subscribe to our mailing list and get interesting stuff and updates to your email inbox.

Thank you for subscribing.

Something went wrong.

Search

Categories