Thanks to Anoop and Juergen for your clarify.
That is only my trivial suggestion of redefinition semantics for 0xF.
After all, 0xF has been a valid value of flow label. Originally, I just
think only 20-bits is enough.
To say the least, Flow label TC need really a wildcard？In a application
RFC 3595 - Textual Conventions for IPv6 Flow Label refers to:
"IPv6FlowLabelOrAny ::= TEXTUAL-CONVENTION
DISPLAY-HINT "d"
STATUS current
DESCRIPTION "The flow identifier or Flow Label in an IPv6
packet header that may be used to discriminate
