People often wonder what the "bis" means in the title of IETF protocol specifications, such as rfc3920bis. The term comes from the Latin word "bis" meaning "twice". For example the Latin proverb "Qui scribit bis legit" means "one who writes, reads twice", and the word "biscuit" comes from "bis" + "coctus" (the past participle of "coquere" meaning "to cook") since originally biscuits were cooked twice (first baked and then slowly dried at a lower temperature). So you can think of a "bis draft" as a twice-baked protocol. :)