http://www.rfc-editor.org/rfc/rfc8300.txt
RFC 8300: Network Service Header (NSH), P. Quinn, U. Elzur, C. Pignataro2018-01-01T23:00:00-00:00This document describes a Network Service Header (NSH) imposed on packets or frames to realize Service Function Paths (SFPs). The NSH also provides a mechanism for metadata exchange along the instantiated service paths. The NSH is the Service Function Chaining (SFC) encapsulation required to support the SFC architecture (defined in RFC 7665).