Cisco CCNP and CCIE Study Notes

Consider the following from a router configured for IPv6 routing

R2#ping ipv6 FE80::A8BB:CCFF:FE00:8300
Output Interface: ethernet0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to FE80::A8BB:CCFF:FE00:8300, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/24/32 ms
R2#ping ipv6 2001:1111::A8BB:CCFF:FE00:8300

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001:1111::A8BB:CCFF:FE00:8300, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/24/40 ms
R2#

Why was I prompted for an output interface for the first ping command but not for the second ping command?