2001-06-29 2010-10-06 IETF consensus 0 Datagram contains a Multicast Listener Discovery message 1 Datagram contains RSVP message 2 Datagram contains an Active Networks message 3 Reserved 4-35 Aggregated Reservation Nesting Level 36-67 QoS NSLP Aggregation Levels 0-31 68 NSIS NATFW NSLP 69-65502 Unassigned 65503-65534 Reserved for experimental use 65535 Reserved The Internet Assigned Numbers Authority