Policy Statement on Address Space Allocations

Alex.Bligh amb at Xara.NET
Tue Jan 30 10:48:59 UTC 1996

"Robert A. Rosenberg" <hal9001 at panix.com> wrote:
> At 6:09 1/29/96, Alex.Bligh wrote:
> > Currently I have 2 choices as
> >far as I can make out, give them a bit of my /19, break up my
> >nice aggregate and ensure loads of extra announcements (and that
> >probably none of them get routed by anyone applying prefix based
> >filtering), or give them a new /19 all of their own (you've
> >said it, that's the minimum size allocation) which actually
> >solves their problem and mine, but this isn't an option
> >currently available because currently it's one window per local-IR.
> >So they have to go and become a local IR.
> If the high /21 of your /19 is not Allocated, you just assign it to them
> and add ONE announcement of the /21 to supersede with the current /19. If
> it is not free but is sparsely populated you can move the stuff out to free
> it up or go to RIPE to get your /19 turned into an /18 (ie: get the /19
> right after your current /19 [RIPE did give you the first /19 in a shorter
> prefix block didn't they?]) in exchange for returning the /21 worth of
> space [giving you 3 extra /21s worth of space], and divide that 2nd /19
> into a /20, and 2 /21s giving them the 2nd /21 (still doing the same 2
> announcements as you would if allocated out of your current /19).

Thankyou for the first constructive workable suggestion had so far. However,
this has two problems.

a) RIPE fidn't give me the first /19 in a shorted prefix block
   ( its x.x.160.x and .192.x is used), but no matter, I'll renumber
   if necessary :-( or persuade them to give me a /18 as well so I
   can do the above (hopefully).
b) The /21 advert may be inbound filtered by a.n.other, which will be
   fine if it has an AS-Path through me (as the less specific route
   will work the same way) but won't when that path goes through the
   other provider with whom they are multi-homed, as the /21 will disappear
   entirely (3rd parties, i.e. a.n.other's customers will see neither),
   the /19 will be the only thing that is visible, and I'll just black
   hole their packets.

Anyway this is several times better than the swamp. Oh well.

Alex Bligh
Xara Networks

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