Policy Statement on Address Space Allocations
Robert A. Rosenberg
Wed Jan 31 09:19:00 CET 1996
At 5:48 1/30/96, Alex.Bligh wrote: >Thankyou for the first constructive workable suggestion had so far. However, >this has two problems. You're welcome. > >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). My convert the /19 to an /18 was a way to get minimal extra announcements. Getting a new /19 and keeping the first 3 /21s for your own use and giving them the 4th, still adds only one EXTRA announcement (over the need to announce the [new] /19 itself). >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. As a Multi-Home (as opposed to a Private) /21 it should (theoretically) be entitled to being added to the filter lists as valid - Getting this done is a political problem. You should not be black holing the packets since your receipt of them is VALID (since they are Multi-Homed as opposed to having walked with the block).
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