ownership, leasing, renumbering, and that draft

[Robert Elz <[e-mail]>]

I have been quiet on this list for some time now, since
starting all this debate by daring to question the merits
of the draft under consideration (draft-ietf-cidrd-ownership-01.txt)

Since then I have been told that it is improper to object to
a draft without proposing an alternative, which I knew of
course in any case, [and which is usually a reasonable position
(occasionally something is simply so brain dead and unworkable
that even without an alternative it must be opposed)] and so
proposed a couple of alternatives in my original message.

I have also been told that it is not permitted to mention any
alternatives on this list, as this isn't the list for that
(that is, this isn't the working group for that).

Consequently, in this message you won't find me expressing a
direct opinion on what should be done with the draft, as doing
that without proposing an alternative (assuming of course, that
I would be objecting to its progress) is not the best thing to
do, and the latter is out of order.  Oh well, perhaps you can
draw your own conclusions from the facts/opinions that I think
I am permitted to send here - or perhaps more accurately, which
haven't yet been ruled out of order.   Note that if a chair, AD,
or doc author, questions this message with a response like
"Well, what else can we do?" I will take that as an explicit
OK to go ahead and post my suggestions, and debate their merits.

First, on the question of what is the current state of play
with regard to address assignments, and whether this draft is
changing the state of the world, or merely making explicit
something that was always there, but hidden ... clearly this
is a change.   It may have never been expressly stated that
numbers allocated were owned (what does it really mean to own
a number anyway), it has however always been assumed (and
practised) that a number once allocated remained with the
organisation it was allocated to as long as that organisation
desired to retain it.  That is, more precisely, that number
would not be allocated to any other organisation.  There is a
long established principle (of law) that permitting a state
of affairs to remain long enough, and allowing others to rely
on that, abrogates any right to claim otherwise.

Now this is not, of itself, an objection to the aim of the
draft, but to the way it is written.  That is, if address
leasing is decided to be the way the Internet needs to move,
then that decision should be made in a frank and honest way.
That is, the draft should simply say words like "Until now,
addresses have been allocated in perpetuity, this cannot
continue (for reasons explained), and consequently a change
needs to be made.   This document makes that change".

Second, there exist words in the draft that exempt existing
numbers from this scheme.  I have some comments on that.

First, the most minor issue is existing "as of when", which has
been asked before.  And answered as well.  This is not really
important - it's a pick a date, and be done with it, though the
draft should be more explicit about just when that date is,
perhaps with words like "as of the publishing of this draft
as an RFC".

What is relevant is what is the definition of "allocated" at
that time, whatever it is.   If I go to my service provider a
week or two after the operative date, and ask for a new number,
and the service provider allocates it out of a block they
obtained before the relevant date, is that an "already allocated"
number or not?   If I have a number I have had allocated for years
now (say one from the SRI NIC, to put it in perspective), but
which hasn't been used for almost as many years, that is, it
is not currently consuming any of the precious router table
space, is that number exempt from renumbering should I decide
to start using it again?

For a draft attempting to set in place a major policy initiative
this one is terribly lacking in detail.

Next, on the same issue, are we guaranteed that existing
numbers, however they are defined, as of the relevant date,
will never need to be renumbered?    Who is in the position to
make that guarantee?   Is the cidrd working group able to
force providers to accept ancient old numbers and provide
routing for them?   Since this doc is proposing means of
keeping routing working, isn't it rather a cop out to simply
ignore all the existing address allocations, as if they weren't
a major (perhaps the major) part of the problem being faced?

Would it not be better, if leasing and renumbering is the
solution to the world's routing problems, to simply make
the policy apply to everyone - which avoids all of the above
definition problems?   Of course it does rather raise the
issue a little higher among those IETF people who get to
decide on whether the draft should move forward or not, at the
minute everyone taking any notice of this issue (or essentially
all of them) can sit back "this doesn't affect me" and allow
it to slide by - which wouldn't happen if all of those people
were faced with renumbering.

On a related issue, every time a concern is expressed by someone,
on how they would not be able to renumber, the standard answer
is "this doesn't apply to you, only new allocations".  That is
an inappropriate response.   True, it deals with the particular
case raised, but fails to notice that these are just examples
of situations that arise all the time.  New organisations, not
yet connected, and not yet holding immutable numbers will find
themselves in all of the same situations as those of us who
are connected now, with all of the same problems we would face
if forced to renumber.   When responding to those who object
on this basis, the defenders of the draft should look beyond the
immediate objection, and into the reasoning behind the
objection, and explain how a new organisation, not yet
connected, not yet with a number, and consequently not yet with
the knowledge, even if with the means, to object, would avoid
the problems posed by those who do now have a connection, but
are being exempted from this draft.

Then there is the qualification that private nets are not a
concern of this draft, it applies only to "the Internet".
At first glance that seems resaonable, people building their
own private nets can use any numbers at all, right?   That
is, those defined for the purpose in RFC1597 (or its successor
when, and if, published), or simply any other numbers picked
at random.

Well, not quite.   This ignores the value of addresses assigned
to be unique, world wide, regardless of to what the addresses
are connected.   There seems to be some view prevalent that
there is the Internet, and it is important, and then there is
everything else, and that is all irrelevant.   All those other
nets have just the same needs as the Internet - they are just
typically a little smaller (or a lot smaller).   Two
organisations that wish to connect to each other need to agree
on a numbering plan that avoids conflicts - they need some
address allocation organisation to deal with this.  Of course,
for two of them, even several hundred, that isn't hard.

Where the difficulty arises is where two such private nets
decide to interconnect, having previously used independant
number allocation plans.   Nightmare is the correct description
of the results - however of course the draft's standard answer,
"renumber", is a plausible solution.   If the two medium sized
nets that are now to connect are doing that as two entities,
and are able to renumber, then that solution even works.

However consider the case where the two nets are not connecting,
instead one organisation connected to one of those nets wants
a connection to the other (simultaneously).  That organisation
can renumber itself, if necessary, so as to remain unique on
both of the nets to which it is connected, but how can it
renumber other organisations on the two nets, which know nothing
about each other, have no intent to communicate with each other,
but happen to have picked the same net numbers?  If my
organisation sends a packet addressed to 10.1.2.3 (where both of
the other organisations have selected net 10 from 1597), how is
my router supposed to decide to whom to send it?   Sounds a
little difficult to me.

There is a reason that unique numbers have always been
recommended to everyone, connecting to the Internet or not
(and which is why there are more non-connected allocated numbers
than connected ones).   It wasn't just that it "seemed good
at the time".  When we start to break the kinds of assumptions
that are the basis of the IP protocol suite we really need to
be very sure that we know exactly what we are doing, and that
we have considered all of the ramifications.  The answer "we
don't know any other way to survive" probably just means "we
aren't bright enough", and should lead to more work to look
for a solution that has probably been there all the time,
unnoticed.

Now I imagine that those who are going to object to this have
already got out their "irrelevant to this draft" big red
pens, or whatever, as 1597 address allocations are not being
directly addressed in it, and the question of whather they are
a good thing or not belongs in another discussion.

Yes, so it does - with one caveat, and that is that this draft
doesn't change anything wrt those kinds of allocations (or non
allocations).  Unfortunately, it does.  The problem relates to
just who does address assignments.  If address assignments are
now to be leases from providers, to whom does an organisation
without a provider turn if they decide that they need a unique
address?

One of the standard rebuttals to this is "the Internet shouldn't
be subsidising outsiders", and nor should it - the organisation
requesting a number should be paying whatever costs are incurred
in granting that request, however that certainly is a side
issue that isn't relevant here.

If addresses are still to be available to outsiders, from
somewhere, so they can have addresses that are known unique,
and which they can use to build their own private (though
possibly large) independant nets, and then interconnect with
each other, then what is the relationship of those numbers
and this draft?

If the organisation, whatever it is, that granted these numbers
finds that its original lease for its address block has expired,
and that it cannot be renewed, what happens to the addresses
it has allocated to unconnected third parties?   Is it really
correct to claim that this draft does not apply to such cases?

If the effect of this draft is that unique addresses are no
longer to be available to non-Internet-connected organisations,
then it should say so explicitly, and justify that decision.

Recall, this is the IETF - the IETF makes standards for all
users of the IP protocol suite, not just the connected Internet.
Anything published with the IETF stamp of approval should be
able to apply equally to all users of the IP protocols.

And finally (I hope) for this message, the draft claims that
an option for a site faced with renumbering is to decide not to
do so, and accept limited connectivity instead.   Let's
examine that option for a minute, and let's take the best
possible case for this to apply.

Assume that a site (X) has an IP number that has been leased to
them, and connects to a provider (P) using that address.  
Further assume that the only party with whom X has any interest
in communicating is one other site (Y) which happens,
conveniently, and probably not accidentally, to have a
connection to the same provider (P).    Now assume that X's
address lease expires, and for whatever reason, it decides that
renumbering is not an option for it.

The draft covers this case explicitly, or it seems to ...

   If the organization doesn't require Internet-wide IP connectivity,
   then renumbering can be avoided. In this case the organization may
   still maintain limited IP connectivity (e.g. with all the subscribers
   of its direct provider) by limiting the scope of its routing
   exception to its direct provider.

Now that fits X perfectly, that is exactly what X doesn't
require, all it needs is connectivity to Y.   Consequently,
it accepts the terms of the draft, has its routing advertisments
limited to its direct provider (P), where they still reach Y,
and in theory, everyone is happy.

But what about the rest of P's customers?   We assume it has
some here.  If P is routing packets bound for X's address to
X, as it has to do to retain connectivity between X and Y, how
do any of the rest of those people manage to communicate with
whoever has been reassigned the address that was (nominally)
taken from X when its lease expired?

Of course, there is a hidden assumption here, which is that
addresses reclaimed upon lease expiry can be reallocated.
Address conservation issues would tend to support this as
a reasonable practice, but perhaps that is not what the draft
intends, I can't find any explicit statement on that issue
one way or the other.   Perhaps one should be added so this
question can be addressed more precisely.

Perhaps the aim is that addresses, once expired will be placed
into a pool of "unable to be used or routed" addresses, and
forgotten, or something.

Note that X might have come to P from provider Q, precisely to
get connectivity to Y (perhaps with some service guarantees
that couldn't be met via whatever connectivity existed between
P and Q) bearing an address that was allocated (leased) by Q
originally.   X is still unable, or unwilling, to renumber.
So P's other customers can continue to continue to communicate
with all of Q's customers, existing and future, Q needs to
remember that it never actually received the address back from
X, and so never allocate it again.   Further, the relationship
between Q and X might not be good, X may refuse to tell Q even
if it does stop using the address - P may also not be a good
friend of Q's, and even if it is, doesn't necessarily know all
of X's intentions.   So there is no way that Q can tell that the
address is now free for use in the general case - it really has
to assume that it is immediately free after the lease has expired
(plus any grace period), or it has to assume it is never
available for re-use.

This won't (needn't) have any adverse implications for the
routing system, but it seems it may have in other areas.

Of course, the alternative would be to delete this paragraph
about limited connectivity (offering a little hope to those for
whom renumbering is not a viable option) and replace it with
one that explicitly says "renumber or no connectivity", but
perhaps that might be too politically sensitive to attempt.

There's also the waffle about what size prefixes can be
moved around without renumbering, which has been pointed out
before, and which I find one of the most imprecise and
meaningless specifications I have ever seen (it leaves the
"best" of the used car contracts for dead).

To finish, I find the draft imprecise, incomplete, inaccurate,
lacking in intellectual honesty, and impossible to actually
use for any practical purposes.

However, I am not permitted to draw a conclusion from that,
as to what should be done with it, as before doing so I would
need to offer an alternative.  I will not suggest new words for
a draft I feel is fatally flawed in any case - that would be
a waste of effort, and I am not permitted to offer my
alternative, so at this point I think I have to leave it to
others in the working group to make up their own minds - and
eventually the IETF as a whole.

kre