[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: (RFC 1888) 00 01 02 03 RFC 4548

Network Working Group                                         Eric Gray
Internet Draft                                          John Rutemiller
Obsoletes: 1888                               Marconi Corporation, plc.
Category: Standards Track                                George Swallow
Expiration Date: June 2006                          Cisco Systems, Inc.
                                                          December 2005

           Internet Code Point Assignments for NSAP Addresses
                        draft-gray-rfc1888bis-03


Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   This document may not be modified, and derivative works of it may
   not be created, except to publish it as an RFC, reformat it for
   readability or translate it into languages other than English.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress".

   The list of current Internet-Drafts can be accessed at:
       http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at:
       http://www.ietf.org/shadow.html


Abstract

   This document is intended to accomplish two highly inter-related
   tasks: to establish an "initial" Internet Code Point (ICP) assignment
   for each of IPv4 and IPv6 address encoding in Network Service Access
   Point (NSAP) Addresses, and to recommend an IANA assignment policy
   for currently unassigned ICP values. In the first task, this document
   is a partial replacement for RFC 1888 - particularly for section 6 of
   RFC 1888. In the second task, this document incorporates wording and
   specifications from ITU recommendation X.213 and further recommends
   that IANA use the "IETF consensus" assignment policy in making future
   ICP assignments.




Internet Draft              Expires June 2006                   Page 1
Gray, et al         Internet Code Point Assignments      December 2005

                             TABLE OF CONTENTS

   1. Introduction ..................................................  2
   1.1. Conventions .................................................  3
   1.2. Acronyms and Terminology ....................................  3
   2. IANA Considerations ...........................................  3
   3. Initial Allocations and Uses ..................................  4
   3.1. IPv4 Address Encoding in an NSAPA ...........................  4
   3.2. IPv6 Address Encoding in an NSAPA ...........................  5
   4. Security Considerations .......................................  6
   5. References ....................................................  6
   5.1 Normative References .........................................  6
   5.2 Informative References .......................................  6
   6. Author Information ............................................  7
   7. Copyright Notice ..............................................  7
   8. Intellectual Property Notice ..................................  8
   9. Acknowledgement ...............................................  8


1. Introduction

   Section 6 of RFC 1888 [1888] previously provided for assignment of
   the initial Internet Code Point (ICP) value '0' for encoding an IPv6
   address in a Network Service Access (or Attachment) Point (NSAP)
   address. RFC 1888 also defined multiple means for restricted encoding
   of an NSAP address in an IPv6 address.

   The means RFC 1888 defined for encoding NSAP addresses in IPv6
   address format, was heavily annotated with warnings and limitations
   that apply should this encoding be used. Possibly as a result, these
   encodings are not used and appear never to have been used in any IPv6
   deployment. In addition, section 6 contains minor errors. As a result
   of these various considerations, RFC 1888 [1888] has been obsoleted
   and declared Historic by RFC 4048 [4048].

   It is the belief of the authors of this document that the errors in
   section 6 of RFC 1888 were - at least in part - the result of the
   fact that the ITU specification [X.213] that originally assigned
   Authority and Format Indentifier (AFI) 35 to IANA was not freely
   publicized, nor was it incorporated or explained using the mechanism
   commonly used in the IETF - i.e. - via an RFC.

   It is therefore part of the purpose of this document to provide that
   explanation.

   In addition, because there are other documents that refer to the IPv6
   ICP assignment in RFC 1888, it is necessary for the errors in section
   6 of RFC 1888 to be corrected - irrespective of the RFC's ultimate
   status.

   Finally, no previous RFC - including RFC 1888 - has ever formalized


Internet Draft              Expires June 2006                   Page 2
Gray, et al         Internet Code Point Assignments      December 2005


   an assignment of an IPv4 ICP. This may have been - in part - because
   of a lack of formal definition of an IANA assignment policy for ICP
   values under the IANA allocated AFI (35).

   This document replaces section 6 of RFC 1888 in defining the ICP for
   IPv6 address encoding in an NSAP address - and - formalizes the ICP
   assignment for IPv4 address encoding in an NSAP address.

1.1. Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [2119].

1.2. Acronyms and Terminology

   AFI   - Authority and Format Identifier
   BCD   - Binary Coded Decimal
   DSP   - Domain Specific Part
   IANA  - Internet Assigned Number Authority
   ICP   - Internet Code Point
   IDI   - Initial Domain Identifier
   IDP   - Initial Domain Part
   IETF  - Internet Engineering Task Force
   ISO   - International Standardization Organization
   NSAP  - Network Service Access (or Attachment) Point (often NSAPA)
   NSAPA - NSAP Address; 20 Octet Address Format
   OSI   - Open Systems Interconnect
   RFC   - Request For Comments
   WIP   - Work In Progress


2. IANA Considerations

   An ITU Recommendation [X.213] has allocated two AFI designating IANA
   as the assignment authority. One of these two AFI ('34') is allocated
   for assignment of NSAPA in Decimal Numeric Format. This document does
   not address allocation for this AFI as it is not clear what - if any
   - use can be made of this encoding format at this time. The other AFI
   ('35') is to be used for binary encoding except as noted below.

   The NSAPA format consists of an Initial Domain Part (IDP) and Domain
   Specific Part (DSP).  The IDP, in turn, consists of an Authority and
   Format Identifier (AFI) and an Initial Domain Identifier (IDI). The
   AFI is defined to be a binary octet and the IDI is defined to be four
   decimal encoded in two octets using Binary Coded Decimal format.
   Each nibble of the IDI is used to represent a decimal digit - using
   binary value '0000' through '1001'.

   In assigning allocation authority for AFI '35' to IANA, ITU-T


Internet Draft              Expires June 2006                   Page 3
Gray, et al         Internet Code Point Assignments      December 2005


   [X.213] recommendation specifies that the two octet IDI will be used
   to hold an Internet Code Point (ICP) which - because of the decimal
   encoding - MUST be in the decimal range from '0' to '9999'.

   The ITU recommendation assumes the assignment of ICP '0' (zero) for
   IPv6 address encoding in an Network Service Access Point Address
   (NSAPA or - often - NSAP). In addition, ITU-T assumed that IANA
   would assign an ICP for IPv4 address encoding in an NSAPA and X.213
   assumes that the ICP value for this purpose would be '1'.

   In an NSAPA, the DSP is the remaining octets after the IDP. For AFI
   '35', this is 17 octets having a format as defined by IANA - or as
   defined by another party and published with IANA consent.

   IANA - as the Authority responsible for the Authority and Format
   Identifier (AFI) '35' - SHOULD NOT assign an ICP unless there is
   a corresponding defined, and published, format at the time of the
   code point assignment.

   Given consent of IANA, the following ICP values are assigned on
   approval of this document:

       ICP Value   Address Encoding   Format Definition
       ----------  -----------------  ----------------------------
          '0'           IPv6          <this document>, section 3.2
          '1'           IPv4          <this document>, section 3.1

   Remaining decimal values '2' through '9999' MUST be assigned on an
   IETF consensus basis [2434].


3. Initial Allocations and Uses

   This document continues the ICP assignment and format definition as
   previously defined in RFC 1888, and formalizes the allocation of ICP
   value '1' for IPv4 encoding and the format to be used. The sections
   below describe the specific IPv4 and IPv6 address encoding formats.

3.1. IPv4 Address Encoding in an NSAPA

   If it is required, for whatever reason, to embed an IPv4 address
   inside a 20-octet NSAP address, then the following format MUST be
   used. Note: alignment is an artifact of existing NSAPA usage.

   A specific possible use of this embedding is to express an IP address
   within the ATM Forum address format.  Another possible use would be
   to allow CLNP packets that encapsulate IPv4 packets to be routed in a
   CLNP network using the IPv4 address architecture. Several leading
   octets of the IPv4 address could be used as a CLNP routing prefix.



Internet Draft              Expires June 2006                   Page 4
Gray, et al         Internet Code Point Assignments      December 2005


   An NSAPA with an AFI value of '35' and an ICP value of '1' (one)
   encodes a 4 octet IPv4 address in the first 4 octets of the DSP.
   The last 13 octets of the DSP are unspecified in this document.  To
   maintain compatibility with both NSAP format and IPv4 addressing,
   these octets MUST be present, but have no intrinsic significance
   for IPv4. The default values for the unspecified octets is zero.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 0-3  |  AFI = 0x35   |   ICP = 0001                  | IPv4 (octet 0)|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 4-7  |             IPv4 (octets 1-3)                 |               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 8-11 |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 12-15|                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 16-19|                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   An NSAPA with the IANA AFI code and ICP set to '1' (one) is converted
   to an IPv4 address by stripping off the first 3 and the last 13
   octets.  If the NSAP addressed contents are passed to a higher layer,
   the last 13 octets SHOULD be presented to the higher layer as well.

   If an NSAP address using this encoding is used for routing in an IPv4
   routing architecture, only the 4 octet IPv4 address MAY be considered.

3.2. IPv6 Address Encoding in an NSAPA

   If it is required, for whatever reason, to embed an IPv6 address
   inside a 20-octet NSAP address, then the following format MUST be
   used. Note: alignment is an artifact of existing NSAPA usage.

   A specific possible use of this embedding is to express an IP address
   within the ATM Forum address format.  Another possible use would be
   to allow CLNP packets that encapsulate IPv6 packets to be routed in a
   CLNP network using the IPv6 address architecture. Several leading
   octets of the IPv6 address could be used as a CLNP routing prefix.

   An NSAPA with an AFI value of '35' and an ICP value of '0' (zero)
   encodes a 16 octet IPv6 address in the first 16 octets of the DSP.
   The last octet of the DSP is a selector.  To maintain compatibility
   with both NSAP format and IPv6 addressing, this octet MUST be
   present, but it has no intrinsic significance for IPv6. Its default
   value is zero, but other values may be used as specified for any
   specific application. For example, this octet may be used to specify
   one of 255 possible port numbers.


Internet Draft              Expires June 2006                   Page 5
Gray, et al         Internet Code Point Assignments      December 2005

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 0-3  |  AFI = 0x35   |   ICP = 0000                  | IPv6 (octet 0)|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 4-7  |             IPv6 (octets 1-4)                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 8-11 |             IPv6 (octets 5-8)                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 12-15|             IPv6 (octets 9-12)                                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 16-19|       IPv6 (octets 13-15)                     |               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   An NSAPA with the IANA AFI code and ICP set to '0' (zero) is
   converted to an IPv6 address by stripping off the first three and the
   twentieth octets. If the NSAP addressed contents are passed to a
   higher layer, the last octet SHOULD be presented to the higher layer
   as well.

   If an NSAP address using this encoding is used for routing in an IPv6
   routing architecture, only the 16 octet IPv6 address MAY be
   considered.

4. Security Considerations

   The NSAP encoding of IPv4 and IPv6 addresses is compatible with the
   corresponding security mechanisms of RFC 2401 [2401], hence this
   document introduces no new security exposure in the Internet.

5. References

5.1 Normative References

   [BCP78] BCP 78/RFC 3667, "IETF Rights in Contributions", Scott
           Bradner, February 2004.

   [BCP79] BCP 79/RFC 3979, "Intellectual Property Rights in IETF
           Technology, Scott Bradner, March 2005.

   [2401]  Successor to RFC 2401, "Security Architecture for the
           Internet Protocol" (draft-ietf-ipsec-rfc2401bis-06),
           Work in Progress, Stephen Kent and Karen Seo, March 2005.

   [2119]  RFC 2119 / BCP 14, "Key words for use in RFCs to Indicate
           Requirement Levels", Scott Bradner, March 1997.

   [NSAP]  International Standardization Organization, "Information
           technology - Open Systems Interconnection - Network service
           Definition", ISO/IEC 8348:2002, 2002.


Internet Draft              Expires June 2006                   Page 6
Gray, et al         Internet Code Point Assignments      December 2005




   [X.213] ITU-T Recommendation X.213, X-Series Recommendations, Data
           Networks and Open Systems Communications, October, 2001.

   [2434]  RFC 2434, "Guidelines for Writing an IANA Considerations
           Section in RFCs", Thomas Narten and Harald Alvestrand,
           October 1998.


5.2 Informative References

   [1888]  RFC 1888, "OSI NSAPs and IPv6", J. Bound, et al, August 1996.

   [4048]  RFC 4048, "RFC 1888 is Obsolete", Brian Carpenter, April 2005.


6. Author Information

   Eric Gray
   Marconi Corporation, plc.
   900 Chelmsford Street
   Lowell, MA, 01851
   E-Mail: Eric.Gray@Marconi.com

   John Rutemiller
   Marconi Corporation, plc.
   3000 Marconi Drive
   Warrendale, PA, 15086-7502
   E-Mail: John.Rutemiller@Marconi.com

   George Swallow
   Cisco Systems, Inc.
   1414 Massachusetts Avenue
   Boxborough, MA, 01719
   E-Mail: swallow@cisco.com


7. Copyright Notice

   Copyright (C) The Internet Society (2005).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Internet Draft              Expires June 2006                   Page 7
Gray, et al         Internet Code Point Assignments      December 2005


8. Intellectual Property Notice

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

9. Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.
























Internet Draft              Expires June 2006                   Page 8


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/