Without the ISP having total control over the customer router, a misconfiguration of filters on the customer side could easily cause the customer to be a valid (and 1 hop) path in the tables from ISP A to ISP B. Doesn't sound like a possibility I would be willing to have hanging over my head.
Well, since my bandwidth is necessary for my business, I think I'd be much more concerned about becomming the valid route than my upstreams, if they get better routing through me, it's not necessarily a bad thing for them unless they're concerned about me snarfing traffic. Plus, you can filter out what you send to me if you're my upstream. That means you'll need a misconfigured router on your side *and* one on mine. I don't know your competency, but I'm fairly certain of mine ;). I put a lot more time, effort and care into choosing a provider than you do into choosing a customer. I don't think it's as big of an issue, other than the obvious effects of router filtering performance, and the chance that the upstream could hose his filters when he goes to listen for routes to me from external sources if he's already got major paranoia filters. Hopefully, he's got that filtered to only happen from my other peering points though. It's not rocket science, but it does take some care in set-up. You have as much chance of getting control of my gateway routers as you have of turning into a purple poodle. I'd purchase Yet Another Service Provider and route a tier lower before I'd play that game. I've got a lot more to lose than my upstreams. Paul ------------------------------------------------------------------------- Paul D. Robertson gatekeeper@gannett.com