On Nov 30, 2011, at 9:14 PM 11/30/11, Pete Resnick 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. Another suggestion was the use of 10.64.0.0/10, with the argument that some devices may use 10.0.0.0 but those devices tend to start numbering with 10.0.0.0/24 or 10.0.1.0/24 and none would use addresses in 10.64.0.0/10. Is there evidence that there are deployments today of devices that use addresses in 10.64.0.0/10? - Ralph > 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 > > 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/> > > Qualcomm Incorporated - Direct phone: (858)651-4478, Fax: (858)651-1102 > _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf