Rajagopalan, B., "Documentation of IANA Assignments for Label Distribution Protocol (LDP), Resource ReSerVation Protocol (RSVP), and Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE) Extensions for Optical UNI Signaling", RFC 3476, DOI 10.17487/RFC3476, March 2003, <https://www.rfc-editor.org/info/rfc3476>.