[sig-policy] prop-061-v002: Autonomous System Numbers (ASN) for document
Below is an updated version of the proposal that includes the amendment
that reached consensus in the Policy SIG yesterday. Specifically,
section 4 of the proposal was amended to state that APNIC is to assign
a block of 16 AS numbers from both the 16-bit and 32-bit AS number
pools for documentation purposes.
The proposal's history can be found at:
Randy and Jian
prop-061-v002: Autonomous System Numbers (ASN) for documentation
Authors: Philip Smith
pfs at cisco dot com
Gaurab Raj Upadhaya
gaurab at lahai dot com
yoshida at nttv6 dot jp
Date: 29 August 2008
This proposal contains the element of the proposal that reached
consensus following community discussion at the APNIC 26 Policy SIG
on Thursday 28 August 2008.
This document discusses the requirement to assign a block of 16-bit
ASNs and a block of 32-bit ASNs for the sole purpose of assisting the
creation of Internet related documentation.
2. Summary of current problem
No portion of the original 16-bit ASN space is available for
For 32-bit ASNs, the AS space above 65535 (or 1.0 in "dot" notation)
is either reserved for future use or allocated, with no portion of the
space available for documentation purposes.
Authors often need to include example address space and AS numbers
when documenting the Internet and the configuration of equipment used
in the operation of the Internet.
Authors currently use Internet resources from a variety of sources.
The following examples describe typical example usage of such Internet
1. Using private address space and/or private AS space
RFC 1918  address space is often used for documentation
requiring the use of IPv4 address space. It's not ideal, but
given that the addresses look like the rest of IPv4 address
space, and that it is an ISP BCP to filter private addresses
out of Internet announcements, its use protects against
The AS range 64512 to 65534  is often used for documentation
requiring the use of 16-bit AS numbers. Most ISPs
automatically filter private ASNs out of the AS path as they
announce them to the Internet, so the use of private ASNs for
documentation is not normally a problem.
Many ISPs also use private ASNs for multihoming customers as
per RFC2270 , and private ASNs are also used inside BGP
2. Resources assigned for documentation purposes
RFC 3849  describes an IPv6 address block which can be used
exclusively for documentation purposes.
3. Using Internet resources from their employer.
This is easy to do, and this resource is typical of that which
is routed on the Internet.
4. Using Internet resources of a typical network on the Internet.
Quite often the resources of the larger and more commonly known
ISPs are used in examples.
5. Easy to remember address values and ASNs are used.
Typical examples might be 184.108.40.206, 220.127.116.11, AS100, AS2.4 and so
on. Quite often these resources are from existing allocations.
6. Resources from ranges unassigned/unallocated at the time the
documentation is written have been used.
For example, ASNs above 48000, or the network 222/8 address
block have been used.
There are two major problems with the last four options above:
- Readers, especially those who are learning about the Internet,
do tend to cut and paste the configuration examples onto running
equipment. Quite often this lab equipment is connected to a
live production network, causing confusion and disruption to the
innocent network used in the example. The Internet today is a
serious commercial entity with the vast majority of business
participating in it attributing a serious portion of their
annual revenue to business done over the net. Dealing with a
denial of service attack caused by an innocent cut and paste by
a student of the industry has in the past caused major revenue
loss for some organisations this has the potential to reoccur in
- Using address and AS space which is unused at the time the
documentation is written means that at some stage in the near
future the examples can disrupt real live networks, as has just
been discussed in the previous point.
3. Situation in other RIRs
The RIRs currently have no formal common policy for making a 32-bit
ASN allocation exclusively for documentation purposes.
4. Details of the proposal
It is proposed that APNIC assign a block of sixteen 16-bit and 32-bit
ASNs to be used solely for the purpose of documentation.
These blocks would be suitable for a modern network topology to
include either exclusive 32-bit ASN or a mixture of 16-bit or 32-bit
ASNs for purposes of documenting relationships between ASNs.
5. Advantages and disadvantages of the proposal
- Authors of documentation and Internet books no longer have to use
32-bit ASNs which belong to their employer (and risk causing
disruption to their employers business), or using 32-bit ASNs
allocated to random organisations around the Internet (and risk
causing disruption to a multitude of organisations). With the
16-bit documentation range, they also don't have to resort to
using the private ASN space.
- Acceptance of this proposal will mean that a block of sixteen
16-bit and 32-bit ASNs will be added to the non-routable ASN
space of the Internet. They will need to be added to the
existing AS_PATH filter list used by all ISPs, in the same way
that RFC 1918 and RFC 3849 address space should never appear on
the public Internet.
- Acceptance of this proposal could potentially make some people
believe that this ASN block is effectively private ASN space as
it is not routable.
- If this proposal is rejected, authors will have to carry on with
the practice highlighted in the Background section of this
proposal, with the associated risks to the integrity of the
6. Effect on APNIC members
This proposal has no direct effect on APNIC members.
7. Effect on NIRs
This proposal has no direct effect on NIRs.
 RFC 1918, Address Allocation for Private Internets
 Autonomous System (AS) Numbers,
 RFC 2270, Using a Dedicated AS for Sites Homed to a Single Provider
 RFC 5065, Autonomous System Confederations for BGP
 RFC 3849, IPv6 Address Prefix Reserved for Documentation