Let's check the interface after the configuration:
ipv6 address 2001:1001::/64 eui-64
Link-local address is derived from EUI-64 format.
R1#show ipv6 interface ethernet 1/0 Ethernet1/0 is up, line protocol is up IPv6 is enabled, link-local address is FE80::CE00:22FF:FEA4:10 Global unicast address(es): 2001:1001::CE00:22FF:FEA4:10, subnet is 2001:1001::/64 [EUI] Joined group address(es): FF02::1 FF02::2 FF02::1:FFA4:10 MTU is 1500 bytes ICMP error messages limited to one every 100 milliseconds ICMP redirects are enabled ND DAD is enabled, number of DAD attempts: 1 ND reachable time is 30000 milliseconds
According to EUI-64 format, first "FFFE" is inserted into the middle of mac-address: cc00.22FFFEa4.0010
R1#show interfaces ethernet 1/0 | include Hardware Hardware is AmdP2, address is cc00.22a4.0010 (bia cc00.22a4.0010)
Then 7th bit is inverted: CC is 11001100. So it becomes 11001110 which means CE.
Finally, last value is combined with FE80::
Global unicast address is also derived by adding EUI-64 format to the end of the configured IPv6 address.
You can overwrite the auto-configured values by configuring them manually. Let's do it on R2:
As a result, ping works:
ipv6 address 2001:1001::2/64 ipv6 address fe80::2 link-local
R1#ping ipv6 2001:1001::2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2001:1001::2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/22/36 ms
# DOWNLOAD LAB 24 GNS3 FILE
R2#ping ipv6 2001:1001::CE00:22FF:FEA4:10 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2001:1001::CE00:22FF:FEA4:10, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/24/52 ms