Value,Description,Reference 0,Datagram contains a Multicast Listener Discovery message,[RFC2710] 1,Datagram contains RSVP message,[RFC2711] 2,Datagram contains an Active Networks message,[RFC2711] 3,Reserved,[RFC5350] 4-35,Aggregated Reservation Nesting Level,[RFC3175] 36-67,QoS NSLP Aggregation Levels 0-31,[RFC5974] 68,NSIS NATFW NSLP,[RFC5973] 69,MPLS OAM (DEPRECATED),[RFC7506][RFC9570] 70-65502,Unassigned, 65503-65534,Reserved,[RFC9805] 65535,Reserved,[The Internet Assigned Numbers Authority]