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Re: The Gorgon's Knot. Was: Re: Verio Peering Question
| progressive dampening is much more appealing than | filtering, to solve this problem Filtering was the first attempted solution to CIDR failure. Damping had the advantage of time, reflection, and input from Curtis Villamizar (who I believe invented the first described damping algorithm) and many others, as well as the help from some truly excellent co-authors, patient customers and colleagues. RIPE as a publication venue also had some distinct advantages over IETF and NANOG. | other alternative method ... (ie Multi6 mapped to IPv4, etc). Ah, you're anticipating solution mark III. | I suspect if customers knew routes were being filtered, they | would care a lot. It got put in overnight because nobody had screamed since the first time it had been threatened some months before. The only serious complaint registered was from some competitors who had been allocating from short prefixes they'd obtained in the very new space covered by the filters, which did not, in fact, filter out long prefixes in older swampy but in-use address ranges. Had the competitors in question (also or instead) announced the prefixes they had actually been allocated, they would not have noticed for some time. (Probably someone would have first noticed odd traceroute behaviour towards one of the "holes" in the big short-prefix allocations that didn't work in the intended way when trying to load-balance or recover from a partition. That is, traffic hitting Sprintlink would go to the big network announcing the short prefix, rather than to the other network announcing the hole. And at the time there were no short prefixes, only holes, almost all of which seemed to be singly homed. If someone has NANOG archives from the time, there are some analyses of what got affected. 'Tweren't much on day one, and the filter was a big enough stick that 'tweren't much on day something-hundred either). | This only works because it is targetted at | less-noticeable address blocks Right. Moreover, they were less-noticeable not just because they were small, but because they were totally new. (Or not even yet used). | and exceptions are made for | noticeable address blocks (major site on a /24's). The swamp was the exception. The exception became the swamp. We thought the swamp would drain thanks to PIARA. It didn't, but it didn't become the toxic waste dump either, thanks to good (space) conservation efforts by the RIRs and the community in general. | If | customers knew that this was being done, and there was no | noticeable value created by the change (as is the case now), | they would have a problem. This information probably isn't | included Verio's sales slick, it wouldn't land many sales. If it were, it would be presented as: "Connect to Verio and avoid filtering -- announce everything you like, everyone else is too stupid to protect their networks from such abuse!" Sean.