Re: ARIN IP allocation questionn

[David Schwartz <davids () webmaster com>]

On Thu, 27 Jun 2002 11:18:50 -0600, Joel Baker wrote:

> On Thu, Jun 27, 2002 at 01:56:26AM -0700, David Schwartz wrote:

> > > My *personal* opinion is that wise ISPs only punt customers to ARIN once
> > > they reach the point where they can, in fact, have a normal ARIN netblock
> > > assigned directly to them (currently a /20, unless I slept through another
> > > change...)

> > The guidelines have a strong preference for singly-homed networks to
> > use IP address space allocated to them from their upstreams. I can think
> > of no logical reason* an ISP would prefer their customers to go to ARIN
> > rather than deal with them. The global routing table is better off for it
> > as well, as the customer's /20 would be a new route, rather than being
> > included in their provider's presumably larger block.

> The assumption that the ISP has a larger block is not always a wise one
> to make.

        Worst case, the ISP can take the customer's request to ARIN and request one
twice as large. The ISP can even give the customer most of what's left of its
current allocation and then request another one larger than the one it
currently holds.

> > On the other hand, I can think of many reasons a customer would prefer
> > to deal with ARIN than their upstream, assuming the meager cost wasn't a
> > factor and they don't mind polluting the global table a tad. Of course,
> > that's not really an operational issue.

> Most of the places I've worked would be charging them for the IP usage
> either way, since the ISP has to pay ARIN, eventually...

        Yes, but the ISP pays at most what their customer would, usually less.

> > * The only reason I could possibly think of is if the ISP is afraid that
> > the large allocation will impact their future allocations because they
> > don't have the confidence or competence to extract a proper justification
> > from their customer and present/defend that justification to ARIN when
> > their next allocation comes up. But this wasn't the reason you were
> > thinking of, right?

> See above. Sometimes you have lots of IP space, but nothing *large*, due to
> business constraints.

        Why does this matter? The customer shouldn't particularly care how he gets
his block. One time when I requested a /22 from my provider, I got two /23's.
So what?

> This often changes over time, but some of us don't
> have multiple legacy /16s from Back In The Day (and then again, some of us
> do - but not the 'us' I work for, anymore).

        Well, if you want more IP space, you won't get it by referring your
customer's to ARIN. And the policy that singly-homed customers should
strongly prefer to get IP space from their providers stands.

        DS