This document proposes text aiming at providing clarification to RFC 2598. The primary motivation for this draft is that the definition of EF PHB given in RFC 2598 does not match the intuition of the EF PHB, and has been determined to be unimplementable in a manner compliant with the definition. In particular, no work-conserving scheduler, including all of the schedulers listed in the Implementation Examples section of RFC 2598, can comply with the definition given in that RFC. This draft gives a rigorous definition of EF PHB which in our opinion preserves the spirit of the EF PHB as intended by RFC 2598 while allowing a number of reasonable compliant implementations. The document also provides implementation guidance and lists several possible implementation examples which conform to the definition given in this draft.