Based on William’s logic below, I would advocate for 49. Owen
> On Jun 19, 2017, at 8:05 PM, William Herrin <[email protected]> wrote: > > On Mon, Jun 19, 2017 at 1:37 PM, David R Huberman <[email protected] > <mailto:[email protected]>> wrote: > Based on comments so far, most agree that a /48 should be SWIP'ed since it is > routable on the internet, and since so far the majority seems to think that > /56 is small enough to not require SWIP, this leaves 7 choices of /49 to /55 > to set the limit for SWIP in the Draft. > > I think that when we consider SWIP boundaries, we should take into account > strictly technical considerations, and not arbitrary ones. I think the > argument for requiring a /48 or larger to be SWIPed is well-grounded in > network engineering practices. I'm not sure I understand the technical > argument for anything smaller than a /48 being mandatory. > > Hi David, > > The obvious technical argument against Nibble "or larger" is that it > encourages assignment on non-niblle boundaries. If /56 requires SWIP, the ISP > has reason to assign /57 instead of /56. That makes IPv6 assignment as messy > as IPv4. If instead /55 requires SWIP, the likely ISP default value becomes > /56, a good nibble-boundary choice. A policy which starts requiring SWIP at > Nibble+1 implicitly encourages the ISP to set their default assignment size > at a nibble boundary which is well-grounded in network engineering practices > > So first and foremost it is technologically correct to set the SWIP boundary > to start at "larger than Nibble" or "Nibble+1 or larger." > > Since "larger than /48" and "/47 or larger" are ruled out by /48's > independent routability (also a technical consideration) and /64 is ruled out > for preventing the intended end-user IPv6 routing ability (also a technical > consideration), that leaves "larger than" /52, /56 and /60 as the only > -technically reasonable- options. > > Regards, > Bill Herrin > > > -- > William Herrin ................ [email protected] > <mailto:[email protected]> [email protected] <mailto:[email protected]> > Dirtside Systems ......... Web: <http://www.dirtside.com/ > <http://www.dirtside.com/>> > _______________________________________________ > PPML > You are receiving this message because you are subscribed to > the ARIN Public Policy Mailing List ([email protected]). > Unsubscribe or manage your mailing list subscription at: > http://lists.arin.net/mailman/listinfo/arin-ppml > Please contact [email protected] if you experience any issues.
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