On Dec 4, 2011, at 11:20 AM, David Conrad wrote: > It isn't a question of whether CGN can be deployed, it is a question of how. As far as I can tell, lack of the a new /10 will simply mean ISPs get to make an operational decision, the result of which will either be more rapid exhaustion of the remaining IPv4 free pools or the use of already allocated space with the potential collisions it entails. It may mean "more rapid exhaustion of the free pool" for a short time, but at some not-too-far-away time it will stop meaning that since the free pool will be exhausted. So that's not a long-term result of not allocating a /10, and thus the phrase "either ... or" used in your email does not apply. ISTM, ISPs would really be left with 4 choices: 1) Use whatever address space they have already now as this new CGN space, such that they stop advertising the space in BGP etc., and migrate all of their existing customers to a model where this previously-public address space is now private and behind CGNs. That's not a result I think we should want to happen, both because it disrupts the current working IPv4 and because it limits potential new ISPs. (it gives an advantage to legacy ISPs with lots of existing v4 addresses) 2) "Squat" on someone else's space or un-allocated space. I don't think that's a result we should want to happen, for obvious reasons. (I also don't think it's likely many ISPs would do this either - just noting it's possible) 3) Use RFC-1918 address space. That would work for pure "consumer" applications, but would break things like remote employees using VPNs. I don't think that's a result we should want to happen, because it affects "good-citizen" Enterprises who aren't even using that ISP while their employees are using the ISP. 4) The CGN vendors and ISPs create a "CGN Forum" industry association, pool money together and buy the space to use from others. I'm not sure if that's a good or bad result, but at the going rate it would ~$50 Million as someone else has mentioned. (Cerner bought Borders' for $12 per IP, and Microsoft bought some of Nortel's for about the same price per IP) I don't know if the interested parties could really get $50 Million together, nor whom they could buy it from. Perhaps they could convince one of the CGN vendors or ISPs who already have large space to part with it for a price. 4b) If one were to think evil-ly, one thing a big CGN vendor could do is use some of their own address space for *their* CGNs, and thereby have a sales advantage over other CGN vendors who weren't given big blocks in years past. I don't think that's a result we should want, either. -hadriel p.s. <rant> and we should really stop talking about this as a "us" vs. "them" problem, or that ISPs are the problem - they're not the cause of the problem, and are coming here for help, and "they" pay for their employee's expenses to be active IETF participants, as well as having been previous financial sponsors of IETF meetings. In short: "they" are "us". *We* have a problem to solve - we can debate if it's solvable, or how to solve it, but not by blaming others. </rant> _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf