Network Working Group                        Internet Architecture Board
Request for Comments: 2200                             J. Postel, Editor


                  INTERNET OFFICIAL PROTOCOL STANDARDS(‘±‚«)


   Some protocols have been superseded by better ones or are otherwise
   unused.  Such protocols are still documented in this memorandum with
   the designation "historic".

   Because it is useful to document the results of early protocol
   research and development work, some of the RFCs document protocols
   which are still in an experimental condition.  The protocols are
   designated "experimental" in this memorandum.  They appear in this
   report as a convenience to the community and not as evidence of their
   standardization.

   Other protocols, such as those developed by other standards
   organizations, or by particular vendors, may be of interest or may be
   recommended for use in the Internet.  The specifications of such
   protocols may be published as RFCs for the convenience of the
   Internet community.  These protocols are labeled "informational" in
   this memorandum.

   In addition to the working groups of the IETF, protocol development
   and experimentation may take place as a result of the work of the
   research groups of the Internet Research Task Force, or the work of
   other individuals interested in Internet protocol development.  The
   the documentation of such experimental work in the RFC series is
   encouraged, but none of this work is considered to be on the track
   for standardization until the IESG has made a recommendation to
   advance the protocol to the proposed standard state.

   A few protocols have achieved widespread implementation without the
   approval of the IESG.  For example, some vendor protocols have become
   very important to the Internet community even though they have not
   been recommended by the IESG.  However, the IAB strongly recommends
   that the standards process be used in the evolution of the protocol
   suite to maximize interoperability (and to prevent incompatible
   protocol requirements from arising).  The use of the terms
   "standard", "draft standard", and "proposed standard" are reserved in
   any RFC or other publication of Internet protocols to only those
   protocols which the IESG has approved.

   In addition to a state (like "Proposed Standard"), a protocol is also
   assigned a status, or requirement level, in this document.  The
   possible requirement levels ("Required", "Recommended", "Elective",
   "Limited Use", and "Not Recommended") are defined in Section 4.2.
   When a protocol is on the standards track, that is in the proposed
   standard, draft standard, or standard state (see Section 5), the
   status shown in Section 6 is the current status.

   Few protocols are required to be implemented in all systems; this is
   because there is such a variety of possible systems, for example,
   gateways, routers, terminal servers, workstations, and multi-user
   hosts.  The requirement level shown in this document is only a one
   word label, which may not be sufficient to characterize the
   implementation requirements for a protocol in all situations.  For
   some protocols, this document contains an additional status paragraph
   (an applicability statement).  In addition, more detailed status
   information may be contained in separate requirements documents (see
   Section 3).