FF02::1:FF0:0/104

 http://en.wikipedia.org/wiki/Solicited-node_multicast_address

A Solicited-Node multicast address is an IPv6 multicast address valid within the local-link (e.g. an Ethernet segment or a Frame Relay cloud). Every IPv6 host will have at least one such address per interface. Solicited-Node multicast addresses are used in Neighbor Discovery Protocol for obtaining the layer 2 link-layer addresses of other nodes.^[1]

A Solicited-Node multicast address is created by taking the last 24 bits of a unicast or anycast address and appending them to the prefix ff02::1:ff00:0/104.^[2] It is important to realize that we have taken 104 bits from the address, so that the last byte of the penultimate field 00 is not used in the prefix.

 ^{ff00:0000   6x4=24} 


A host is required to join a Solicited-Node multicast group for each of its configured unicast or anycast addresses.
Example: If we have an interface with the IP address fe80::2aa:ff:fe28:9c5a the associated Solicited-Node multicast address is ff02::1:ff28:9c5a. So we must join to the multicast group represented by this address.

Working Example

Assume a host needs to make a local delivery to another host on the local network, and the target host has an IPv6 address of fe80::2aa:ff:fe28:9c5a (as in Example 2 above). In order to make a Layer-2 (e.g. Ethernet) delivery, it needs to know the target host's hardware address (e.g. "Ethernet MAC address"). But in order to do this, it must first determine which hardware address to send it to. To do this, an IPv6 host will construct the Solicited-node Multicast Address related to the target address.