http://www.rfc-editor.org/rfc/rfc1809.txt
RFC 1809: Using the Flow Label Field in IPv6, C. Partridge1995-06-01T23:00:00-00:00The purpose of this memo is to distill various opinions and suggestions of the End-to-End Research Group regarding the handling of Flow Labels into a set of suggestions for IPv6. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.