Which Internet control message protocol (ICMPv6) message type would you receive if your
message exceeded the size limit on a network segment?

A.
Parameter problem.

B.
Destination unreachable.

C.
Redirect.

D.
Packet Too Big.

Explanation:
A Packet Too Big MUST be sent by a router in response to a packet that it cannot forward
because the packet is larger than the MTU of the outgoing link. The information in this message is
used as part of the Path MTU Discovery process [PMTU].
Sending a Packet Too Big Message makes an exception to one of the rules of when to send an
ICMPv6 error message, in that unlike other messages, it is sent in response to a packet received
with an IPv6 multicast destination address, or a link-layer multicast or link-layer broadcast
address. (Reference: RFC 2463)
Incorrect Answers:
A: If an IPv6 node processing a packet finds a problem with a field in the IPv6 header or extension
headers such that it cannot complete processing the packet, it MUST discard the packet and
SHOULD send an ICMPv6 Parameter Problem message to the packet’s source, indicating the
type and location of the problem. (Reference: RFC 2463)
B: A Destination Unreachable message SHOULD be generated by a router, or by the IPv6 layer in
the originating node, in response to a packet that cannot be delivered to its destination address for
reasons other than congestion. (An ICMPv6 message MUST NOT be generated if a packet is
dropped due to congestion.)If the reason for the failure to deliver is lack of a matching entry in the
forwarding node’s routing table, the Code field is set to 0 (NOTE: this error can occur only in
nodes that do not hold a “default route” in their routing tables).If the reason for the failure to deliver
is administrative prohibition, e.g., a “firewall filter”, the Code field is set to 1.If there is any other
reason for the failure to deliver, e.g., inability to resolve the IPv6 destination address into a
corresponding link address, or a link-specific problem of some sort, then the Code field is set to
3.A destination node SHOULD send a Destination Unreachable message withCode 4 in response
to a packet for which the transport protocol (e.g., UDP) has no listener, if that transport protocol
has no alternative means to inform the sender. (Reference: RFC 2463)
C: If an IPv6 node processing a packet finds a problem with a field in the IPv6 header or extension
headers such that it cannot complete processing the packet, it MUST discard the packet and
SHOULD send an ICMPv6 Parameter Problem message to the packet’s source, indicating the
type and location of the problem. (Reference: RFC 2463)Neighbor Discovery defines five different
ICMP packet types: A pair of Router Solicitation and Router Advertisement messages, a pair of
Neighbor Solicitation and Neighbor Advertisements messages, and a Redirect Message. The
Redirect is used by routers to inform hosts of a better first hop for a destination. )Reference: RFC
2461)