Also sprach Alex Bligh
Those who propose filtering a la Verio / Sprint(passim) suggest that your incentive to renumber is that certain other (not in the line of transit) networks will not accept these prefixes (or apply more stringent dampening on them), and hence give you inferior routing either permanently (filtering) or temporarilly (dampening), assuming you have a covering netblock.
But that's not an incentive to renumber at all, because I can't go to ARIN and say, "I want to renumber out of these disparate blocks and get one big one that is more globally routable." So renumbering out of the block that I'm thinking of (204.252.74/24, FWIW) still doesn't do me any good.
Of course if you have a swamp /24, the filtering argument doesn't apply, but the dampening one does.
The /24 I mentioned above isn't swampy, but I do have a swamp /24 that we make use of...and it would be one of the more difficult ones for us to renumber out of, but we'd be willing to do for "the good of the Internet" if we weren't going to be stabbed in the back for doing it, which is about the situation as it exists now.
Aside: It's interesting that all the anti-filtering arguments are coming from those who are customers of Filterer's peers. We have heard that Filterer doesn't filter its own customers, but we haven't heard Filterer's BGP customers complaining (at least in this forum) that they are missing routes and hence have suboptimal connectivity to Filterer's peers' customers. As last 3 letters of NANOG indicate, we here should perhaps be interested in designing filtering policies which attract happy paying customers - so far few people have suggested an upstream with aggressive peer filtering is a worse upstream. (Ducks from torrent of mail)
Perhaps that's because all of us that think the filtering is a bad thing wouldn't touch a Filterer's network with a 39 1/2 foot pole. I think its rather a self-selecting sample. Personally, I look forward to the day that a Verio sales rep. calls me trying to sell me transit so I can read him the riot act about their filtering policies. Ultimately, the policies in place for IP allocation *encourage* routing table growth. We can blame Verio, or whoever is filtering, and I believe they do deserve all the flames they get...probably more...as they choose to filter and essentially say, "Screw you, little providers and small corporations, you're not a big boy so you don't deserve robust network connectivity." I do have to reserve some blame for the RIR's as well though. Their policies encourage routing table growth, so they have to share in the blame for that. -- Jeff McAdams Email: jeffm@iglou.com Head Network Administrator Voice: (502) 966-3848 IgLou Internet Services (800) 436-4456