The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Internet Layer (OSI Network Layer) Protocols            9  Internet Control Message Protocol (ICMP/ICMPv4 and ICMPv6)                 9  ICMP Message Types and Formats                      9  ICMP Version 6 (ICMPv6) Informational Message Types and Formats

ICMPv6 Router Advertisement and Router Solicitation Messages 1 2 3 4 ICMPv6 Redirect Messages

Addressing of Neighbor Advertisement and Neighbor Solicitation Messages

Neighbor Solicitation messages are sent either unicast to the address of the target device, or to the solicited-node multicast address of the target. This latter address is a special type used to allow a device to send a multicast that will be heard by the target whose address it is trying to resolve, but won't be heard by most other devices; it is explained in the topic on IPv6 address resolution.

When a Neighbor Advertisement message is generated in response to a Neighbor Solicitation, it is sent unicast back to the device that sent the Solicitation, unless that message was sent from the unspecified address, in which case it is multicast to the “all nodes” multicast address. If the Neighbor Advertisement message is sent unsolicited (for example, by a device that wishes to inform others of a change in link-layer address), it is sent to the “all nodes” multicast address.

ICMPv6 Router Advertisement and Router Solicitation Messages 1 2 3 4 ICMPv6 Redirect Messages