00 - skip over this option and continue processing the header.

   01 - discard the packet.

   10 - 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.

   11 - discard the packet and, only if the packet's Destination
        Address was not a multicast address, send an ICMP Parameter
        Problem, Code 2, message to the packet's Source Address,
        pointing to the unrecognized Option Type.