IANA Allocation Guidelines for the Protocol Field
RFC 5237

Document Type RFC - Best Current Practice (February 2008; Errata)
Updates RFC 2780
Also known as BCP 37
Was draft-arkko-rfc2780-proto-update (individual in int area)
Authors Jari Arkko  , Scott Bradner 
Last updated 2015-10-14
Stream IETF
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Stream WG state (None)
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IESG IESG state RFC 5237 (Best Current Practice)
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Responsible AD Russ Housley
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Network Working Group                                           J. Arkko
Request for Comments: 5237                                      Ericsson
BCP: 37                                                       S. Bradner
Updates: 2780                                         Harvard University
Category: Best Current Practice                            February 2008

           IANA Allocation Guidelines for the Protocol Field

Status of This Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.


   This document revises the IANA guidelines for allocating new Protocol
   field values in IPv4 header.  It modifies the rules specified in RFC
   2780 by removing the Expert Review option.  The change will also
   affect the allocation of Next Header field values in IPv6.

1.  Introduction

   This document revises the IANA guidelines [RFC2780] for allocating
   new Protocol field values in IPv4 header [RFC0791].  The change will
   also be applicable for IPv6, as the IANA guidelines for IPv6 Next
   Header values [RFC2460] allocation refer to the IPv4 guidelines.

   Previously, RFC 2780 allowed such allocations to happen through IESG
   Approval, Standards action, or Expert Review processes
   [RFC2780][RFC2434].  The Expert Review process was specified to be
   used only in the case where a non-disclosure agreement was involved:

      IANA allocates values from the IPv4 Protocol name space following
      an Expert Review, IESG Approval or Standards Action process.  The
      Expert Review process should only be used in those special cases
      where non-disclosure information is involved.  In these cases the
      expert(s) should be designated by the IESG.

   The need for the Standards Action rule is obvious as the IETF keeps
   developing new protocols.  It is equally obvious that there is a need
   to allow experimental allocations in this space; see RFC 4727
   [RFC4727] for an example.  Similarly, there are cases when it makes
   sense to allocate values out of this space for other non-Standards
   Track or non-IETF uses.  However, the size of the field is 256
   values, and 55% of these were in use at the time this document was
   written.  As a result, a sanity check is needed to ensure that

Arkko & Bradner          Best Current Practice                  [Page 1]
RFC 5237               Protocol Field IANA Rules           February 2008

   allocations are not made needlessly.  RFC 2780 specifies the IESG
   Approval rule to take care of these sanity checks for the non-
   Standards Track cases.  The judgment call can take into account the
   existence of a stable protocol specification, constituency that wants
   to use it, need to avoid duplicated allocations for the same purpose,
   whether protocol number allocation is the right solution for this
   problem as opposed to, say, a TCP port, and so on.

   However, we now believe that the non-disclosure agreement option is
   not appropriate for allocations in this space.  Traditionally, non-
   disclosure agreements have been used by the IANA when a company was
   developing a proprietary protocol and did not want to disclose new
   areas of research or future products.  The protocol space is limited
   enough that we no longer believe that it is reasonable to use the
   resource for such proprietary protocols.  Thus, we believe that
   allocations should only be made using the IESG Approval or Standards
   Action processes when there are public specifications that can be

   As a result, this document revises the RFC 2780 rules by removing the
   option for Expert Review for the IPv4 Protocol and IPv6 Next Header
   fields.  This document takes no position on the allocation of other
   parameters with non-disclosure agreements, as those parameters may
   require different policies.

2.  IANA Considerations

   This document replaces the RFC 2780 Section 4.3 rule [RFC2780] with
   the following:

      IANA allocates values from the IPv4 Protocol name space following
      an IESG Approval or Standards Action process.

   This document also makes an implicit change to the rule for the IPv6
   Next Header field in Section 5.3 of RFC 2780.  That rule refers to
   the rule in Section 4.3 of the same RFC.  From now on, this reference
   should be understood to refer to the rule revised here, i.e., without
   the Expert Review option.

3.  Security Considerations

   This specification does not change the security properties of the
   affected protocols.

Arkko & Bradner          Best Current Practice                  [Page 2]
RFC 5237               Protocol Field IANA Rules           February 2008

4.  Acknowledgments

   Issues with the original RFC 2780 rules were uncovered in discussions
   of the IETF-IANA team.  The team also provided background information
   on the practical difficulties encountered with non-disclosure
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