RFC 8200 section 4.2 states that if a node does not recognize an option type, that node must do some action depending on the 2 higher order bits of the option type. When the higher order bits are
01, it is supposed to discard the packet and, regardless of whether or not the packet's Destination Address was a multicast address, send an ICMP Parameter Problem, Code 2, message to the packet's Source Address, pointing to the unrecognized Option Type.
This seems to contradict with RFC 1122 section 3.2.2 which states that An ICMP error message MUST NOT be sent as the result of receiving a datagram destined to an IP broadcast or IP multicast address.
Seems like there is some conflict but RFC 8200 only uses the lowercase of "must" so I would think RFC 1122 takes precendence. If this the case though, does that make action
01 effectively the same as action
10 in practice?