>> And owners of those services >> will simply go to ISPs and say "route this, or I'll find someone else >> who will". And the sales and marketing departments of many ISPs will >> fall over each other to be the first to say "why certainly we'd love >> your business". > > I used to work at a large ISP with exactly these kinds of sales > people. They have a hard time taking "no" for an answer from the > engineers, but when the engineers say "sure we can do it but it isn't > going to work" and then, lo and behold, it doesn't work, they tend to > catch on. > > I.e., you can pay YOUR ISP to route your ULAs, but that doesn't mean > the next ISP is going to accept those advertisements. my experience is that users do get smarter over time. it just takes a long time. the problem is that they're being conditioned to accept that something will work by early behavior of ISPs, when it won't work in the long term. here's the deal: if you get a PA block, it will fail to work if you change ISPs or if the ISP is forced to renumber. if you get a PI block or ULA block, it will fail to work when the ISPs routing complexity gets too great and you can't afford to pay them to route your prefix anymore. so absent some kind of indirection between what hosts see and what ISPs route on, neither arrangement is permanent and neither avoids the need to renumber. > Obviously unbelievable amounts of money will make a difference here, > but how does it make sense to go visit all the largest ISPs handing > out money if you can get a PI or PA block much cheaper and easier? when push comes to shove, I'm not convinced that it will be cheaper to get ISPs to route PI blocks than to route ULA blocks. unless they're somehow aggregatable. Keith _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf