NAIPR Message

Implied warranty of routability? Was: Re: US CODE: Title 15, ...

On Fri, 31 Jan 1997, Stephen Satchell wrote:

> Let's turn down the heat level just a bit and look at something.  One of
> the rationales that has been put forward by proponents is that ARIN would
> allocate net addresses based on procedures that the backbone people have
> agreed to.  This is the reason for the "bloat" in the budget:  you need
> people who understand network architecture to select the "right" block of
> numbers to give to a particular applicant to minimize any bad effect on
> global routers.

Nice theory but it won't work. First of all, there are no procedures that
the core network operators have agreed to. They are independent businesses
and although they must cooperate in the routing of packets, they have
differing network architectures, different kinds of equipment and
different policies and procedures. They don't necessarily all agree how IP
allocation should be done. The policies that ARIN applies are set within
the IETF and more people than just the operators of the defaultless core
are involved in setting those standard policies. Nevertheless there is a
complex interplay between the registries, the standards working groups,
the core operators and other stakeholders. This is why the Board of
Trustees needs to be composed of people who understand how things work.
Partly to ensure that they can do a proper job within ARIN and partly to
ensure that they can communicate and work together with their peers in
other registries, with IANA, with the IETF and with the operators in the
defaultless core, whether those are transit providers like Sprint or
whether they are regional providers like MCS.

> What that says is that a block allocation from ARIN has a much better
> chance of being "routable" than an arbitrary allocation without any
> analysis.  In short, while the ARIN can't guarantee routing, it gives you a
> much clearer chance of getting a routable block in a much shorter
> timeframe.

No. If you get an IP address block from your upstream provider you are
guaranteed 100% to get a routable address block. If you get one from ARIN,
it may or may not be routable. This is not likely to change because not
all organizations who as for unique IP address blocks intend to use them
on the global Internet. And when the core network operators change their
policies, they don't wait for anybody's permission; they just do it. So
the registries will always lag behind the operators.

If there is any single thing that can be done to guarantee the routability
of IP address blocks it is to get them from your upstream provider. And if
you require a Provider Independent (PI) address block then the single most
useful thing you can do to guarantee this is to read and understand the
policies and procedures laid out on the ARIN website at in the Reading List. Routable PI blocks go to those
organizations that can make a credible case to justify their need for

Michael Dillon                   -               Internet & ISP Consulting
Memra Software Inc.              -                  Fax: +1-250-546-3049             -               E-mail: michael at