Dear
SIG members
A
new version of the proposal “prop-111: Request-based expansion
of IPv6
default
allocation size has been sent to the Policy SIG for review.
There
are changes to section 4. Proposed policy solution only.
Information
about earlier versions is available from:
You
are encouraged to express your views on the proposal:
-
Do you support or oppose the proposal?
-
Is there anything in the proposal that is not clear?
-
What change could be made to this proposal to make it more
effective?
Please
find the text of the proposal below.
Kind
Regards,
Andy
and Masato
----------------------------------------------------------------------
prop-111-v004
Request-based expansion of IPv6 default allocation size
----------------------------------------------------------------------
Author:
Tomohiro Fujisaki
1.
Problem statement
--------------------
IPv6
minimum allocation size to LIRs is defined as /32 in the "IPv6
address
allocation and assignment policy"[1]. It's better to
expand
this minimum allocation size up to /29 (/32 - /29) since:
-
Before sparse allocation mechanism implemented in late 2006,
/29
was
reserved for all /32 allocations by sequential allocation
method
made from those old /23 blocks. These reserved blocks
might
be kept unused in the future.
-
Sparse allocation mechanism was implemented in late 2006 with
a
/12
allocation from the IANA. Under the sparse allocation
mechanism,
there is no reservation size defined, and the space
between
allocations continues to change, depending on the
remaining
free pool available in APNIC.
However,
the "APNIC guidelines for IPv6 allocation and
assignment
requests"[2] stated:
"In
accordance with APNIC's "IPv6 address allocation and
assignment
policy", where possible, subsequent delegations to the
same
resource holder are made from an adjacent address block by
growing
the delegation into the free space remaining, unless
disaggregated
ranges are requested for multiple discrete
networks."
So,
it is expected that allocation up to /29 is guaranteed for
consistency
with allocations above. Based on the current
situation,
contiguous allocation of /29 can still be accommodated
even
under the sparse allocation mechanism (Current /32
allocations
from the /12 block can grow up to /24 at this stage).
-
After amended HD Ratio (0.94) and base calculation size (/56)
was
introduced
(prop-031 and prop-033), to obtain address blocks larger
than
/32 and to request additional address blocks became harder
especially
for small and middle size ISPs.
-
For traffic control purpose, some LIRs announce address blocks
longer
than /32 (e.g. /35). However, some ISPs may set filters to
block
address size longer than /32 since some filtering
guidelines
recommend to filter longer prefix than /32([3][4]). If
LIRs
have multiple /32, they can announce these blocks and its
reachability
will be better than longer prefix.
-
If an LIR needs address blocks larger than /32, LIRs may tend
to
announce
as a single prefix if a /29 is allocated initially at
once.
i.e., total number of announced prefixes in case 1 may be
smaller
than in case 2.
case
1:
The
LIR obtains /29 at the beginning of IPv6 network construction.
case
2:
The
LIR obtains /32, and /31, /30 additionally with the subsequent
allocation
mechanism.
2.
Objective of policy change
-----------------------------
This
proposal modifies the eligibility for an organization to
receive
or extend an IPv6 address space up to a /29 (/32 -/29) by
explaining
how the extended space up to /29 will be used.
3.
Situation in other regions
-----------------------------
RIPE-NCC:
The
policy "Extension of IPv6 /32 to /29 on a per-allocation vs
per-LIR
basis" is adopted in RIPE-NCC and LIRs in RIPE region can get
up
to /29 by default.
4.
Proposed policy solution
----------------------------
-
Change the text to "5.2.2 Minimum initial allocation size" of
current
policy document as below:
Organizations
that meet the initial allocation criteria are
eligible
to receive an initial allocation of /32. The organizations
can
receive up to /29 by providing utilization information of the
whole
address
space.
-
Change /32 to /29 in "5.2.3 Larger initial allocations”
Initial
allocations larger than /29 may be justified if:
-
Add following text as 5.3.4
5.3.4
Extend existing allocations to /29
LIRs
that hold one or more IPv6 allocations are able to request
extension
of each of these allocations up to a /29 without meeting
the
utilization rate for subsequent allocation by providing their
network
plan
to show how the whole address space will be used.
5.
Explain the advantages of the proposal
-----------------------------------------
-
It is possible to utilize address blocks which is potentially
unused into the future.
-
Organizations can design their IPv6 networks more flexibly.
-
It will be possible for LIRs to control traffic easier.
6.
Explain the disadvantages of the proposal
--------------------------------------------
Some
people may argue this will lead to inefficient utilization of
IPv6
space since LIRs can obtain huge address size unnecessarily.
However,
this will not happen because larger address size needs
higher
cost to maintain that address block.
7.
Impact on resource holders
-----------------------------
NIRs
must implement this policy if it is implemented by APNIC.
8.
References (if required)
---------------------------
[1]
IPv6 address allocation and assignment policy
[2]
APNIC guidelines for IPv6 allocation and assignment requests
[3]
Packet Filter and Route Filter Recommendation for IPv6 at xSP
routers
[4]
IPv6 BGP filter recommendations