If wfSRsvpSenderAdspecGSSvc is TRUE, this
is the composed value for the guaranteed ser-
vice 'D' parameter since the last reshaping
point. A return of zero or noSuchValue indi-
cates one of the following conditions:
the invalid bit was set
the parameter was not present
If wfSRsvpSenderAdspecGSSvc is FALSE, this
returns zero or noSuchValue.
UNITS, microseconds