Ted, > There are enterprises that currently use > 172.16/12. Yes, but I thought the topic of discussion when I wrote was the default prefix used by mass-market NAT CPE boxes. That's a very different problem than dealing with enterprise networks or even ISPs that have intentionally deployed 172.16/12. I'm not suggesting that reconfiguring those intentional deployments is easy, but then no solution to this problem is easy. Reconfiguring mass-market boxes is simply impossible. Regards Brian On 2011-12-02 11:27, Ted Hardie wrote: > Notes below. > > On Wed, Nov 30, 2011 at 6:14 PM, Pete Resnick <presnick@xxxxxxxxxxxx> wrote: > >> ** >> Daryl, >> >> The problem described in the draft is that CPEs use 1918 space *and that >> many of them can't deal with the fact that there might be addresses on the >> outside interface that are the same as on the inside interface*. The claim >> was made by Randy, among others, that only 192.168/16 space was used by >> such unintelligent CPEs. I believe I have seen the claim that 10/8 space is >> also used in unintelligent equipment that can't deal with identical >> addresses inside and outside. Is there reason to believe that within the >> ISP network / back-office etc. that there is equipment that can't deal with >> 17.16/12 space being on both the inside and outside? I haven't seen anyone >> make that specific claim. >> >> If we know that 172.16/12 used both inside and outside will break a >> significant amount of sites that CGNs will be used with, we can ignore this >> argument. But if not, then let's rewrite the document to say that CGNs >> should use 172.16/12 and that any device that wants to use 172.16/12 needs >> the ability to deal with identical addresses on the inside and the outside >> interface. Of course, all equipment should have always been able to deal >> with identical addresses inside and outside for all 1918 addresses anyway. >> But if we think the impact of using 172.16/12 for this purpose will cause >> minimal harm, then there's no compelling reason to allocate new space for >> this purpose. >> >> pr >> >> > I wrote a response to Brian's original statement then deleted it because I > assumed others would ignore it as clearly last minute and ill-researched. > Apparently, that was wrong. There are enterprises that currently use > 172.16/12. (There are enterprises which use every tiny piece of RFC 1918 > space.) *Any* piece of the current RFC 1918 space you attempt to define as > being used for this will conflict *somewhere*. Anyone who happened to > chose this for an enterprise deployment and gets stuck behind a CGN would > be forced to renumber, in other words, because of this statement. That is, > if they actually followed the statement--they're much more likely to work > with the CGN operator to use squat space on the CGN instead, since that's > the existing way of avoiding this pain. > > Rubbing my crystal ball real hard, in other words, I predict that the > consequences of assigning a piece of existing RFC 1918 space to this at > this late date will have the same consequences as assigning no space at > all, with the addition of a tiny increment of confusion among those souls > who happen to read the RFC and briefly think it reflects reality. > > Either allocate new space or reject; the middle ground of assuming that > some part of RFC 1918 can be safely allocated for this should not be > considered as an option. > > My personal opinion, not that of my employer, spouse, child, or the man on > the street. > > regards, > > Ted > > > > >> On 11/30/11 3:04 PM, Daryl Tanner wrote: >> >> It's not just about the CPE devices and customer LANs. >> >> Address conflicts are also going to happen within the ISP network / >> back-office etc. 172.16.0.0/12 is used there. >> >> >> Daryl >> >> >> On 30 November 2011 20:52, Brian E Carpenter <brian.e.carpenter@xxxxxxxxx>wrote: >> >>> On 2011-12-01 09:28, Chris Grundemann wrote: >>> ... >>>> It is more conservative to share a common pool. >>> It suddenly occurs to me that I don't recall any serious analysis >>> of using 172.16.0.0/12 for this. It is a large chunk of space >>> (a million addresses) and as far as I know it is not used by default >>> in any common CPE devices, which tend to use the other RFC 1918 blocks. >>> >>> I realise that ISPs with more than a million customers would have to >>> re-use this space, whereas a /10 would only bring this problem above 4M >>> customers, but at that scale there would be multiple CGN monsters anyway. >>> >>> Sorry to bring this up on the eve of the telechat. >>> >> -- >> Pete Resnick <http://www.qualcomm.com/~presnick/> <http://www.qualcomm.com/%7Epresnick/> >> Qualcomm Incorporated - Direct phone: (858)651-4478, Fax: (858)651-1102 >> >> >> _______________________________________________ >> Ietf mailing list >> Ietf@xxxxxxxx >> https://www.ietf.org/mailman/listinfo/ietf >> >> > > > ------------------------------------------------------------------------ > > _______________________________________________ > Ietf mailing list > Ietf@xxxxxxxx > https://www.ietf.org/mailman/listinfo/ietf _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf