In general, is it better to have you IP space scattered amongst a lot of
different /24's /25's and /26's or would it be better to collect everything
into a large /19 or /18, when going to BGP4?
I would think the latter. If so, would anyone know why it is that the
backbone providers are so resistant to giving out blocks to do this?
Could it be because they won't be able to do anything with the small
pieces that get returned and those will end up going to waste because
they are so fragmented? Or perhaps they don't even have procedures in
place to do anything with returned address space, yet?
I would think the latter. If so, would anyone know why it is that the
backbone providers are so resistant to giving out blocks to do this?
If backbone operators do not efficiently allocate IP space to their
downstream customers then the next time they need additional IP space they
will not be able to get any. Everyone in the food chain has to operate
under the same policies of justifying IP space based on need and using the
space efficiently. There is more info on this at http://www.arin.net and in
particular you should have a look through the recommended reading section
especially any documents relating to CIDR.
Okay, this is somewhat operational (more policy, but it's
something backbone operators need to think about) -- how
many of y'all actually /do/ have a policy in place for
when your downstream customers want to reaggregate? For
that matter, how many of you have had to think about it
before? (I'm not looking for a show of hands, of course,
just some interesting discussion.)
Personally, I dealt with that somewhat in a previous job,
where we were returning space originally allocated to us
by Net99 (yup, it's a common story), and therefore forcing
just about all of our long-time customers to renumber. It
was not fun, but I tried real hard to make it go well.
So, I figured out which of our customers were in a good
position to be renumbered into a better aggregate block as
long as they were going to have to renumber anyway, and
assigned new addresses accordingly.
The main failing in the plan was that I got assigned to a
different project before the renumbering was completed.
My guess would be that it'd be a little more difficult if
you or your customer were trying to reaggregate without the
impetus that your existing addresses didn't have valid
reverse DNS any more, and were gonna be forcibly reclaimed
in a few months.