Dear SIG members
The proposal 'Format for delegation and recording of 4-byte AS numbers'
been sent to the Policy SIG for review. It will be presented at the Policy SIG
The proposal's history can be found at:
We invite you to review and comment on the proposal on the mailing list before the meeting.
The comment period on the mailing list before an APNIC meeting is an important part of the policy development process. We encourage you to express your views on the proposal:
- Do you support or oppose this proposal?
- Does this proposal solve a problem you are experiencing? If so,
tell the community about your situation.
- Do you see any disadvantages in this proposal?
- Is there anything in the proposal that is not clear?
- What changes could be made to this proposal to make it more
Randy and Jian
prop-065-v001: Format for delegation and recording of 4-byte AS numbers ________________________________________________________________________
Authors: James Spenceley
james at vocus dot com dot au
Date: 22 July 2008
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
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
Defines the 4-byte AS number as:
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" . Version 5 of the
Internet Draft expired 4 June 2008 . And there is no mention of
the ASDOT format in RFC 4893 .
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
Due to these issues, the operator community is hesitant to adopt
It is likely, however, that the format used by RIRs, has, or
certainly will, lead to routing vendors implementing the RIR format
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
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
RIPE NCC: ASDOT & ASPLAIN
Assignment: AfriNIC: ASDOT
RIPE NCC: ASDOT
Whois: AfriNIC: 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
- 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
- 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
- Accurate whois information will be returned regardless of whether
the input is in ASPLAIN or ASDOT format.
- 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.
 Canonical Textual Representation of Four-octet AS Numbers http://tools.ietf.org/id/draft-michaelson-4byte-as-representation-00.txt
 RFC 4893 - BGP Support for Four-octet AS Number Space
 Canonical Textual Representation of Four-octet AS Numbers http://tools.ietf.org/id/draft-michaelson-4byte-as-representation-05.txt
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