Policy Statement on Address Space Allocations
Robert A. Rosenberg
Wed Jan 31 09:17:50 CET 1996
At 11:39 1/30/96, Iljitsch van Beijnum 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 > >Suppose you have a customer that needs a /22 and they want to go >multi-homed. Suppose you give them that /22 out of your /19 or /16 you >got from the RIPE NCC. So they announce their /22 to you and to their >other provider. But you keep announcing your /19 or /16. So if anybody >were to filter the /22 announcement, your customer only suffers partial >loss of connectivity, since you are still announcing an aggregate of >their announcemnt (your original /19 or /16). > >Problem fixed. Anything else? ;-) Unless you announce both the /16 (or 19) AND the /22, they are not multi-homed but only single routed (with some fallback for those who see the /22 announcement). Anyone who gets the unfiltered /22 announcement will used the other provider (so long as that provider is up) while you get used only by those who get a filter routing (and as fallback when the other provider goes down).
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