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prop-065-v001: Format for delegation and recording of 4-byte AS numbers
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Authors:   James Spenceley
           james@vocus.com.au

Version:   1

Date:      22 July 2008


1.  Introduction
----------------

This proposal recommends that APNIC changes its procedures to
standardise on delegating 4-byte AS numbers in the ASPLAIN format rather
than the current ASDOT format.

This proposal extends to the data recorded in APNIC Whois Database
records, with the proposal recommending that whois returns the same
record for queries made in either format.


2.  Summary of current problem
------------------------------


2.1 Definitions

    ASPLAIN
     
       Defines the 4-byte AS Number as a basic 32 bit integer, it is the
       current format used to represent 2-byte AS numbers. For example:

          Original 2-byte AS pool:    0 - 65535
          New 4-byte AS pool:         0 - 4294967295

    ASDOT
    
       Defines the 4-byte AS number as:

          <higher16bits>.<lower16bits>

       For example:

          1.4541 would be used to represent the 32 bit integer 70077


2.2 Current format used by RIRs and IANA

    The RIRs and IANA currently use the ASDOT format to refer to 4-byte
    AS numbers. However, there appears to be no reason that ASDOT has
    become the default format used by these organizations.

    ASDOT was first documented in the Internet Draft, "Canonical Textual
    Representation of Four-octet AS Numbers" [1]. Version 5 of the
    Internet Draft expired 4 June 2008 [2]. And there is no mention of
    the ASDOT format in RFC 4893 [3].

    ASDOT is widely regarding as being incompatible with a number of
    operational systems and router configurations. Specifically, the '.'
    within the AS number is incompatible with IRR and RPSL. It also has
    the potential to break many regular expressions in existing router
    configurations.

    Due to these issues, the operator community is hesitant to adopt
    ASDOT.

    It is likely, however, that the format used by RIRs, has, or
    certainly will, lead to routing vendors implementing the RIR format
    as standard.

    If there is widespread adoption of ASDOT, it should be by considered
    choice rather than as a result of the RIRs using this format when
    informing networks of the AS number they have been delegated.

    APNIC members have never been consulted as to the format they would
    prefer for representation of 4-byte AS numbers. This proposal seeks
    to raise consensus from the membership for representation of 4-byte
    AS numbers in the ASPLAIN format by APNIC.


2.3 APNIC Whois Database

    Currently APNIC records 4-byte AS numbers only in ASDOT format which
    leads to whois only reporting results for queries entered in this
    format. An operator wishing to find whois information for an ASPLAIN
    number must manually convert to ASDOT before querying the whois.
    This conversion is open to operator error.

2.4 Format currently used by APNIC

    APNIC currently refers to 4-byte AS numbers in the following manner:

        Website:     ASDOT
        Assignment:  ASDOT
        Whois:       ASDOT


3.  Situation in other RIRs
---------------------------

This proposal may be submitted in the other regions in the near future.

The practice of referring to and recording 4-byte AS numbers in other
RIRs is as follows:

    Website:         AfriNIC:   Neither
                     ARIN:      ASDOT & ASPLAIN
                     LACNIC:    Neither
                     RIPE NCC:  ASDOT & ASPLAIN


    Assignment:      AfriNIC:   ASDOT
                     ARIN:      ASDOT
                     LACNIC:    ASDOT
                     RIPE NCC:  ASDOT


    Whois:           AfriNIC:   ASDOT
                     ARIN:      ASDOT
                     LACNIC:    ASDOT
                     RIPE NCC:  ASDOT


4.  Details of the proposal
---------------------------

4.1 It is proposed that APNIC adopt ASPLAIN as the default format for
    documenting 4-byte AS numbers.


4.2 To maintain a level of compatibility with the ASDOT format currently
    in use, this proposal recommends that the APNIC Whois Database be
    modified to return the same record for queries submitted in either
    ASDOT or ASPLAIN format.


4.3 Upon endorsement by the APNIC Executive Council, APNIC would
    document delegations of all 4-byte AS numbers in ASPLAIN format and
    migrate existing whois data.


5.  Advantages and disadvantages of the proposal
------------------------------------------------

5.1 Advantages

    - 4-byte AS numbers will be delegate and recorded in the same method
      that has been used for 2-byte delegations.

    - 4-byte AS numbers will be delegated and recorded in a format that
      is the  most backward compatible with current systems and 
      configurations.

    - ASPLAIN format is most backwards compatable with current IRR and
      RPSL and the absences of the '." means it is compatable with the
      the majority of regular expressions in use.

      This sets the default standard for delegation and reference to 4-
      byte AS numbers in most backwards compatible format.

      Quote:      "Avoiding needless change means stuff keeps working"
                                                Paul Jakma - Ripe 55

    - Less change is required by operators, which makes it more likely
      to be widely adopted.

    - 4-byte AS numbers will be delegate and recorded in the format
      used in RFC 4893.

    - There will be a documented standard for delegation of 4-byte AS
      numbers.

    - Accurate whois information will be returned regardless of whether
      the input is in ASPLAIN or ASDOT format.


5.2 Disadvantages

    - While 4-byte AS numbers have a lower numeric value, their
      representation is more easily remembered in the ASDOT format. For
      example, "AS2.4" rather than "131076". However, this advantage is
      negated as the numeric values of 4-byte AS number grow larger.

    - If the ASDOT format is adopted in future to refer and configure
      4-byte AS numbers, then data will need to be modified again.


6.  Effect on APNIC members
---------------------------

The proposal impacts all APNIC members.


7.  Effect on NIRs
------------------

The proposal has no direct impact on NIRs. NIRs may choose to record
delegations and report whois information in the format of their choice.


8.  References
--------------

[1] Canonical Textual Representation of Four-octet AS Numbers
http://tools.ietf.org/id/draft-michaelson-4byte-as-representation-00.txt


[2] RFC 4893 - BGP Support for Four-octet AS Number Space
    http://www.ietf.org/rfc/rfc4893.txt


[3] Canonical Textual Representation of Four-octet AS Numbers  http://tools.ietf.org/id/draft-michaelson-4byte-as-representation-05.txt