A solicited-node multicast address is an IPv6 multicast address used by the Neighbor Discovery Protocol to determine the link layer address associated with a given IPv6 address, which is also used to check if an address is already being used by the local-link or not, through a process called DAD (Duplicate Address Detection). The solicited-node multicast addresses are generated from the host's IPv6 unicast or anycast address, and each interface must have a solicited-node multicast address associated with it.
A solicited-node address is created by taking the least-significant 24 bits of a unicast or anycast address and appending them to the prefix ff02::1:ff00:0/104.[1]
Assume a host with an unicast/anycast IPv6 address of fe80::2aa:ff:fe28:9c5a. Its solicited-node multicast address will be ff02::1:ff28:9c5a.
fe80::2aa:ff:fe28:9c5a IPv6 unicast/anycast address (compressed notation)
fe80:0000:0000:0000:02aa:00ff:fe28:9c5a IPv6 unicast/anycast address (uncompressed notation)
-- ---- the least-significant 24-bits
ff02::1:ff00:0/104 Solicited-Node multicast address prefix
ff02:0000:0000:0000:0000:0001:ff00:0000/104 (uncompressed)
---- ---- ---- ---- ---- ---- -- The first 104 bits
ff02:0000:0000:0000:0000:0001:ff28:9c5a Solicited-Node multicast address (uncompressed notation)
ff02::1:ff28:9c5a Solicited-Node multicast address (compressed notation)
A solicited-node multicast MAC address is an Ethernet multicast address used by the Neighbor Discovery Protocol as a destination MAC address when communicating to hosts using a solicited-node multicast address. Each interface must be listening to its solicited-node multicast MAC address associated to them.
It is created by taking the least-significant 24 bits of a solicited-node multicast address and appending them to the prefix 33:33:FF:xx:xx:xx.[2]