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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) Error Message Types and Formats

ICMPv6 Packet Too Big Messages 1 2 ICMPv6 Parameter Problem Messages

ICMPv6 Time Exceeded Message Format

The format for ICMPv6 Time Exceeded messages can be found in Table 105 and Figure 155.

In IPv4, ICMP Time Exceeded messages are used both as an error message and in a clever application to implement the TCP/IP traceroute command. This is done by first sending a “dummy” datagram is sent with a Time To Live value of 1, causing the first hop in the route to discard the datagram and send back an ICMP Time Exceeded. Then, a second datagram is sent to the same destination with a TTL value of 2, causing the second device in the route to report back a Time Exceeded, and so on.

There is of course an IPv6 version of traceroute, sometimes called traceroute6. Due to IPv6 and its protocols and applications still being in development, I have not been able to confirm definitively that traceroute6 is implemented using ICMPv6 Time Exceeded messages in the manner described above, but I believe this is the case (and it certainly would make sense.) See the topic discussing traceroute for further information.

ICMPv6 Packet Too Big Messages 1 2 ICMPv6 Parameter Problem Messages