IPv6 Icky EUI-64 Drill 1 – Answers
Short and icky sweet: this post lists answers for the icky EUI-64 drill 1 for #ICND2 and #CCNA. The problems require you to find the IPv6 address a host or router would use, given a prefix, MAC address, and assuming they use stateless auto-configuration. This post lists the answers.
Related links:
The Answers
Table 1 lists the original problems. Table 2 then lists the unicast IPv6 addresses as calculated with EUI-64, before abbreviation, with table 3 listing the same addresses in abbreviated form as requested. Table 4 then lists the solicited node multicast address just for fun. Also, for a quick review, note that the rules for creating the second half of the unicast address using SLAAC is as follows: split the MAC, insert FFFE, and invert the 7th bit. Figure 1 summarizes the process.
Figure 1: EUI-64 Rules Used by SLAAC
Table 1: Original Problems
| Problem # | Prefix | MAC Address |
|---|---|---|
| 1 | 2001:0DB8:9283:0102::/64 | 000C.1234.5678 |
| 2 | 3000:D0D0:0D0D:BEEF::/64 | 0003.0303.0303 |
| 3 | 2001:0DB8:0000:0000::/64 | 0C00.BEEF.CAFE |
| 4 | 3100:0202:0101:00AA::/64 | 0013.0B0B.B0B0 |
| 5 | 2001:0DB8:0000:0000::/64 | 2000.9876.5432 |
Table 2: Unabbreviated Unicast Addresses Found with SLAAC
| Problem # | Unabbreviated Unicast IPv6 Address |
|---|---|
| 1 | 2001:0DB8:9283:0102:020C12FF:FE34:5678 |
| 2 | 3000:D0D0:0D0D:BEEF:0203:03FF:FE03:0303 |
| 3 | 2001:0DB8:0000:0000:0E00:BEFF:FEEF:CAFE |
| 4 | 3100:0202:0101:00AA:0213:0BFF:FE0B:B0B0 |
| 5 | 2001:0DB8:0000:0000:2200:98FF:FE76:5432 |
Table 3: Abbreviated Unicast Addresses Found with SLAAC
| Problem # | Abbreviated Unicast IPv6 Address |
|---|---|
| 1 | 2001:0DB8:9283:0102:020C12FF:FE34:5678 |
| 2 | 3000:D0D0:0D0D:BEEF:0203:03FF:FE03:0303 |
| 3 | 2001:0DB8:0000:0000:0E00:BEFF:FEEF:CAFE |
| 4 | 3100:0202:0101:00AA:0213:0BFF:FE0B:B0B0 |
| 5 | 2001:0DB8:0000:0000:2200:98FF:FE76:5432 |
Table 4: Solicited Node Multicast Addresses
| Solicited Node Multicast Addresses | |
| 1 | FF02::1:FF34:5678 |
| 2 | FF02::1:FF03:303 |
| 3 | FF02::1:FFEF:CAFE |
| 4 | FF02::1:FF0B:B0B0 |
| 5 |
FF02::1:FF76:5432 |
the problem was to write shortest abreviated ipv6 address. answer shows unabreviated version of addresses.
2001:db8:9283:102:20c:12ff:fe34:5678
3000:d0d0:d0d:beef:103:3ff:fe03:3030
2001:db8::f00:beff:feef:cafe
3100:202:1010:aa:213:bff:fe0b:b0b0
2001:db8::2200:98fe:ef76:5432
Keith,
Thanks. Added a table. Appreciate the heads up.
We can also take it to the next step and “shrink” the address to what the router will display:
1 — 2001:DB8:9283:102:20C:12FF:FE34:5678
2 — 3000:D0D0:D0D:BEEF:103:3FF:FE03:3030
3 — 2001:DB8::E00:BEFF:FEEF:CAFE
4 — 3100:202:1010:AA:213:BFF:FE0B:B0B0
5 — 2001:DB8::2200:98FF:FE76:5432
table 3 row 5 second quartet is 0DB8, abbreviated form is DB8.
Also, column heading says “Unabbreviated Unicast IPv6 Addresses” should say “Abbreviated Unicast IPv6 Addresses”
Hey John,
Thanks! Fixed both.
Wendell
When I check this exercise using PT I get an error when the 8th bit is 1 (the second Hex digit is odd: 1,3,5,7,9,B,D,F) I believe that if the 8th bit is 1 the MAC address is classified as multicast. A 0 is unicast.
R1(config)#int gi0/1
R1(config-if)#mac-add 0303.0303.0303
% Malformed hex mac address
Is this a PT issue or is it possible to manually set a multicast MAC address?
Michael,
Thanks so much for the note.
In this case, Packet Tracer is acting just like real gear. Indeed, the issue is the MAC address in problem 2 had the 8th bit set to 1, making it a multicast MAC address, and both real Cisco IOS and packet tracer reject using the MAC address. My mistake for using it in the lab.
I just updated the lab exercise and answer post to use a unicast MAC, by the way.
Thanks for letting me know!
Wendell