Checksum The 16-bit one's complement of the one's complement sum of the ICMP message starting with the ICMP Type. For computing the checksum, the checksum field should be zero. Address mask A 32-bit mask. The structure of the ICMPv6 header is shown in the following illustration. Type The type of the message.
Messages can be error or informational messages.
Packet too big, Time exceed, Parameter problem. The possible informational messages are, Echo Request, Echo Reply, Group Membership Query, Group Membership Report, Group Membership Reduction. For each type of message several different codes are defined. For further details, refer to the standard. Checksum Used to check data corruption in the ICMPv6 message and parts of the IPv6 header.