http://www.rfc-editor.org/rfc/rfc7280.txt
RFC 7280: IANA Guidance for Managing the Unidirectional Lightweight Encapsulation (ULE) Next-Header Registry, G. Fairhurst2014-06-01T23:00:00-00:00This document updates RFC 4326 to clarify and update the allocation rules for the Unidirectional Lightweight Encapsulation (ULE) Next- Header registry. This registry is used by ULE and Generic Stream Encapsulation (GSE) to record the code points of Extension Headers and protocols supported by these encapsulation protocols.