On Tue, Feb 21, 2017 at 02:11:15PM +1300, Brian E Carpenter wrote: > On 21/02/2017 13:19, Job Snijders wrote: > > On Thu, Feb 16, 2017 at 09:40:01AM +0100, otroan@xxxxxxxxxxxxx wrote: > >> There are many reasons for the 64 bit boundary. > >> - Allowing identifier locator split: 8+8 / GSE that led to ILNP and NPT66 > > > > Irrelevant. > > Not really. They are both running code. You may not want them in > *your* network but that isn't the point. Some people want them. > > And there is a lot of other running code too, not just SLAAC which is > mandatory to implement in every IPv6 host. So this actually trumps all > the other arguments: it's 64 bits because it's 64 bits. When someone utters the phrase "it is X because it is X", the rhetorical imperative seems to be to dismiss further conversation (perhaps any internal dialogue as well, which may be the primary purpose). "It is what it is" therefore, there’s nothing more to be said about it... Except when it's not 64 bits? > > If this is the case, why proceed 4291bis while its content is > > contested? > > What we're discussing is the exact text to describe the inconvenient > truth. I'm not aware of any generally available running code that will > be changed in even one instruction by the final text - that is indeed > a requirement for advancement to Internet Standard. The below is truth. AS 2914 is one of the larger Internet backbones. If the Internet Archives are to believed they started deployment of IPv6 15+ years ago. I've looked at all configured IPv6 addresses on AS 2914 equipment. Interestingly enough, the below table is a reflection of not only NTT's own addressing, and (since AS2914's core function is to connect networks to each other) also of its peers and customers. In the end, whatever makes the thing work is the thing that will be configured. /127 - 22% /126 - 52% /125 - 0,9% /124 - 0,5% /120 - 0,04% /112 - 0,02% /64 - 23% The above percentages come from grepping through configurations of thousands of interconnections. I'm confident that other networks will show similar prefix length distributions. I'd be interested to see an accomodation for staticly configured environments in the text. Kind regards, Job