[1] ICMPv6 is an integral part of IPv6 and performs error reporting and diagnostic functions.

The current complete list of assigned ICMPv6 types can be found at this link: IANA: ICMPv6 Parameters.

ICMPv6 provides a minimal level of message integrity verification by the inclusion of a 16-bit checksum in its header.

Unspecified options can be attached to the end: When an ICMPv6 node receives a packet, it must undertake actions that depend on the type of message.

The ICMPv6 protocol must limit the number of error messages sent to the same destination to avoid network overloading.

For example, if a node continues to forward erroneous packets, ICMP will signal the error to the first packet and then do so periodically, with a fixed minimum period or with a fixed network maximum load.