Value,Description,Reference
1,IPv4 prefix,[RFC3209]
2,IPv6 prefix,[RFC3209]
3,Unassigned,
4,Unnumbered Interface ID,[RFC3477]
5,4-byte AS number,[RFC7897][RFC7898]
6,OSPF Area ID,[RFC7897][RFC7898]
7,IS-IS Area ID,[RFC7897][RFC7898]
8,Optical Interface Class List,[RFC8780]
9,Client Signal Information,[RFC8780]
10,Label,[RFC8779]
11-31,Unassigned,
32,Autonomous system number,[RFC3209]
33,Explicit Exclusion Route subobject (EXRS),[RFC4874]
34-127,Unassigned,