--On Friday, 28 March, 2003 14:54 -0500 Keith Moore
<moore(_at_)cs(_dot_)utk(_dot_)edu> wrote:
> Did anybody consider just handing out a /48 (or a bit
> smaller) automagically with each DNS registration?
Routing Table Bloat. If you can figure out how to do this in
a CIDR aggregation context, or otherwise work around the
table problem, the IETF and NANOG will quite certainly
jointly nominate you for sainthood. ;)
...right after you get lynched for heresy.
yeah, well...
Tony is right -- any registration process costs resources. But,
if these addresses are assumed to be not routable, then there
shouldn't be any routing table bloat. Put differently, once can
conceive of three ways to get addresses:
* From an RIR, as PI space
* From an ISP, as PD CIDR space. ISPs might sensibly
decide to charge less (in money or aggravation) for
space which no one intended to route. Or might not: the
marketplace is good at sorting out these things, as long
as the RIRs are willing to make allocations to ISPs that
reflect the desirability of having addresses for
isolated networks unique and reflecting the ISPs to
which they might ultimately connect.
* From some other process, as long-prefix, almost
certainly unroutable, isolated space. This process
could presumably be designed to be very lightweight in
charges and administrative costs.
So, while I'm very hesitant about anything that ties addressing
(of any sort) to DNS names, I'm not convinced that Dave's
suggestion is worth dismissing out of hand.
Three additional observations:
(i) Tony's response to my note seems, to me, to turn SL largely
into a policy problem, not a technical one. We haven't have
really good success binding policies into protocols. That
doesn't convince me that we should never do so, but it does seem
to argue for looking at alternatives, even radical ones.
(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.
(iii) Yes, if I have an odd address and sufficient money, I can
almost certainly convince some ISP to route it. But that ISP's
leverage to get its peers to accept any long-prefix addresses it
happens to offer and route them may be distinctly limited,
especially if, by offering/announcing those addresses, it is
violating a well-understood policy against doing such things.
(For example, an RIR policy that made PI address allocations
much more difficult for ISPs who were guilty of routing table
pollution by short prefixes could really focus the attention.)
So it seems to me to be plausible to suggest that the right
place to prevent routing table explosion (or even "bloat") is in
routing decisions and acceptance of announcements, and not in
creating special address scopes.
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.
john