The Free On-line Dictionary of Computing (30 December 2018):

Internet-Draft
I-D

   (I-D) A draft working document of the Internet Engineering
   Task Force, its Areas, and its Working Groups.  As the name
   implies, Internet-Drafts are purely discussion documents with
   no formal status.  They are valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents
   at any time.  Very often, an I-D is a precursor to a Request
   For Comments.

   (1994-12-08)