To mount a CD or DVD from the CLI use:

# mount -V cdrfs -o ro /dev/cd0 /mnt
# df -g /mnt
Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/cd0           3.64      0.00  100%  1905950   100% /mnt

To mount a iso image on the /mnt directory use:

# loopmount -i aix61_dvd.iso -o "-V cdrfs -o ro" -m /mnt 
# df -g /mnt
Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/loop0         3.64      0.00  100%  1905950   100% /mnt