John C Klensin wrote:
(ii) ISPs impose restrictions on their customers all the time
and often even enforce them. Many of us consider some of these
to be desirable (e.g., terms and conditions prohibiting
spamming) and others less so (e.g., prohibitions against running
server or peer-peer protocols over a cable network or address
restrictions that force reasonably-architected LANs into NAT
arrangements) but the conditions clearly exist.
Note I said:
It is absolutely unreasonable for an ISP to tell their customer
anything about running their network that is not directely
related to the customer/provider interface. As long as the
enterprise traffic over that interface is related to the
capabilities they are paying for, it is none of the ISPs
(or IETFs) business what they are doing elsewhere.
The ISPs do set terms for the customer/provider interface all the time,
and rightly so. They can not restrict me from setting up an 802.11 link
to my neighbor, only that my neighbor is not allowed to use that for
access to the provider's network. In a similar vein, the provider is not
in a position to tell customers what address space they can use for
purposes that do not interact with the provider interface. They can try,
and in a monopoly environment will probably succeed. That does not mean
we can tell ISPs to require that people not use any given address space
just because the provider is supplying another one.
I also note that site local addresses open up a whole series of
questions about "locality" and scope-range. Perhaps we also
need "ISP-local" addresses (routing into one ISP's space, or
part of it, but not to that ISP's peers or transit customers)
and so on. The one thing that can be guaranteed about that sort
of arrangement is an extension of the "pay enough and someone
will route it" model will apply: If some ISP sees a potential
competitive advantage in offering such a product (and
addresses), the product will follow soon thereafter. And,
again, I think that this suggests that we had better figures out
how to deal with these things on a policy basis, not a
protocol-imbedded special address scope one. We are almost
certain to have the policy problem anyway and it is not clear
that special cases for peculiar address scopes will buy us that
much in addition.
Address filtering exists in the network today, and will continue. Since
that is done as an expression of local policies, you are correct the
whole discussion is really about policy. It is not clear to me what the
IETF is in a position to do, other than define the operation of a
multifacited DNS. ;)
Tony