for assigning numbers to name spaces.

   Not all name spaces require centralized administration.  In some
   cases, it is possible to delegate a name space in such a way that
   further assignments can be made independently and with no further
   (central) coordination. In the Domain Name System, for example, the
   IANA only deals with assignments at the higher-levels, while
   subdomains are administered by the organization to which the space
   has been delegated. As another example, Object Identifiers (OIDs) as
   defined by the ITU are also delegated [ASSIGNED].  When a name space




 
RFC 2434           Guidelines for IANA Considerations       October 1998


   can be delegated, the IANA only deals with assignments at the top
   level.

   This document uses the terms 'MUST', 'SHOULD' and 'MAY', and their
   negatives, in the way described in RFC 2119 [KEYWORDS]. In this case,
   "the specification" as used by RFC 2119 refers to the processing of
   protocols being submitted to the IETF standards process.

2.  Issues To Consider

   The primary issue to consider in managing a name space is its size.
   If the space is small and limited in size, assignments must be made
   carefully to insure that the space doesn't become exhausted. If the
   space is essentially unlimited, on the other hand, it may be
   perfectly reasonable to hand out new values to anyone that wants one.
   Even when the space is essentially unlimited, however, it is usually
   desirable to have a minimal review to prevent the hoarding of or
   unnecessary wasting of a space. For example, if the space consists of
   text strings, it may be desirable to prevent organizations from
   obtaining large sets of strings that correspond to the "best" names
   (e.g., existing company names).

   A second consideration is whether it makes sense to delegate the name
   space in some manner. This route should be pursued when appropriate,
   as it lessens the burden on the IANA for dealing with assignments.

   In some cases, the name space is essentially unlimited, and assigned
   numbers can safely be given out to anyone. When no subjective review
   is needed, the IANA can make assignments directly, provided that the
   IANA is given specific instructions on what types of requests it
   should grant, and what information must be provided before a request
   for an assigned number will be considered. Note that the IANA will
   not define an assignment policy; it should be given a set of
   guidelines that allow it to make allocation decisions with little
   subjectivity.

   In most cases, some review of prospective allocations is appropriate,
   and the question becomes who should perform the review and how
   rigorous the review needs to be.  In many cases, one might think that
   an IETF Working Group (WG) familiar with the name space at hand
   should be consulted. In practice, however, WGs eventually disband, so
   they cannot be considered a permanent evaluator. It is also possible
   for name spaces to be created through individual submission
   documents, for which no WG is ever formed.

   One way to insure community review of prospective assignments is to
   have the requester submit a document for publication as an RFC. Such
   an action insures that the IESG and relevant WGs review the




 
RFC 2434           Guidelines for IANA Considerations       October 1998


   assignment. This is the preferred way of insuring review, and is
   particularly important if any potential interoperability issues can
   arise. For example, many assignments are not just assignments, but
   also involve an element of protocol specification. A new option may
   define fields that need to be parsed and acted on, which (if
   specified poorly) may not fit cleanly with the architecture of other
   options or the base protocols on which they are built.

   In some cases, however, the burden of publishing an RFC in order to
   get an assignment is excessive. However, it is generally still useful
   (and sometimes necessary) to discuss proposed additions on a mailing
   list dedicated to the purpose (e.g., the ietf-types@iana.org for
   media types) or on a more general mailing list (e.g., that of a
   current or former IETF WG).  Such a mailing list provides a way for
   new registrations to be publicly reviewed prior to getting assigned,
   or to give advice for persons who want help in understanding what a
   proper registration should contain.

   While discussion on a mailing list can provide valuable technical
   expertise, opinions may vary and discussions may continue for some
   time without resolution.  In addition, the IANA cannot participate in
   all of these mailing lists and cannot determine if or when such
   discussions reach consensus.  Therefore, the IANA cannot allow
   general mailing lists to fill the role of providing definitive
   recommendations regarding a registration question.  Instead, the IANA
   will use a designated subject matter expert.  The IANA will rely on a