On Wed, Dec 4, 2013 at 2:25 PM, Brian Dickson <brian.peter.dick...@gmail.com> wrote: > Not necessarily transit - leaf ASN ISP networks (which do IP transit for > consumers, but do not have BGP customers) would also be counted in. They do > still exist, right?
that's still a transit as, right? I think your math means that there would only ever be 16k networks.. which seems small. > On Wed, Dec 4, 2013 at 1:35 PM, Christopher Morrow <morrowc.li...@gmail.com> > wrote: >> >> On Wed, Dec 4, 2013 at 1:32 PM, Rob Seastrom <r...@seastrom.com> wrote: >> > >> > Brian Dickson <brian.peter.dick...@gmail.com> writes: >> > >> >> Rob Seastrom wrote: >> >> >> >>> "Ricky Beam" <jfbeam at >> >>> gmail.com<http://mailman.nanog.org/mailman/listinfo/nanog>> >> >>> writes: >> >>> > >> >>> * On Fri, 29 Nov 2013 08:39:59 -0500, Rob Seastrom <rs at seastrom.com >> >>> <http://mailman.nanog.org/mailman/listinfo/nanog>> wrote: *>> >> >>> * So there really is no excuse on AT&T's part for the /60s on uverse >> >>> 6rd... *> >> >>> * ... *> >> >>> * Handing out /56's like Pez is just wasting address space -- someone >> >>> *> >> >>> * *is* paying for that space. Yes, it's waste; giving everyone 256 *> >> >>> * networks when they're only ever likely to use one or two (or maybe >> >>> *> >> >>> * four), is intentionally wasting space you could've assigned to *> >> >>> * someone else. (or **sold** to someone else :-)) IPv6 may be huge to >> >>> *> >> >>> * the power of huge, but it's still finite. People like you are *> >> >>> * repeating the same mistakes from the early days of IPv4... * There's >> >>> finite, and then there's finite. Please complete the >> >>> following math assignment so as to calibrate your perceptions before >> >>> leveling further allegations of profligate waste. >> >>> Suppose that every mobile phone on the face of the planet was an "end >> >>> site" in the classic sense and got a /48 (because miraculously, >> >>> the mobile providers aren't being stingy). >> >>> Now give such a phone to every human on the face of the earth. >> >>> Unfortunately for our conservation efforts, every person with a >> >>> cell phone is actually the cousin of either Avi Freedman or Vijay >> >>> Gill, and consequently actually has FIVE cell phones on active >> >>> plans at any given time. >> >>> Assume 2:1 overprovisioning of address space because per Cameron >> >>> Byrne's comments on ARIN 2013-2, the cellular equipment providers >> >>> can't seem to figure out how to have N+1 or N+2 redundancy rather >> >>> than 2N redundancy on Home Agent hardware. >> >>> What percentage of the total available IPv6 space have we burned >> >>> through in this scenario? Show your work. >> >>> -r >> >> >> >> >> >> Here's the problem with the math, presuming everyone gets roughly the >> >> same >> >> answer: >> >> The efficiency (number of prefixes vs total space) is only achieved if >> >> there is a "flat" network, >> >> which carries every IPv6 prefix (i.e. that there is no aggregation >> >> being >> >> done). >> >> >> >> This means 1:1 router slots (for routes) vs prefixes, globally, or even >> >> internally on ISP networks. >> >> >> >> If any ISP has > 1M customers, oops. So, we need to aggregate. >> >> >> >> Basically, the problem space (waste) boils down to the question, "How >> >> many >> >> levels of aggregation are needed"? >> >> >> >> If you have variable POP sizes, region sizes, and assign/aggregate >> >> towards >> >> customers topologically, the result is: >> >> - the need to maintain power-of-2 address block sizes (for >> >> aggregation), >> >> plus >> >> - the need to aggregate at each level (to keep #prefixes sane) plus >> >> - asymmetric sizes which don't often end up being just short of the >> >> next >> >> power-of-2 >> >> - equals (necessarily) low utilization rates >> >> - i.e. much larger prefixes than would be suggested by "flat" >> >> allocation >> >> from a single pool. >> >> >> >> Here's a worked example, for a hypothetical big consumer ISP: >> >> - 22 POPs with "core" devices >> >> - each POP has anywhere from 2 to 20 "border" devices (feeding access >> >> devices) >> >> - each "border" has 5 to 100 "access" devices >> >> - each access device has up to 5000 customers >> >> >> >> Rounding up each, using max(count-per-level) as the basis, we get: >> >> 5000->8192 (2^13) >> >> 100->128 (2^7) >> >> 20->32 (2^5) >> >> 22->32 (2^5) >> >> 5+5+7+13=30 bits of aggregation >> >> 2^30 of /48 = /18 >> >> This leaves room for 2^10 such ISPs (a mere 1024), from the current /8. >> >> A thousand ISPs seems like a lot, but consider this: the ISP we did >> >> this >> >> for, might only have 3M customers. >> >> Scale this up (horizontally or vertically or both), and it is >> >> dangerously >> >> close to capacity already. >> >> >> >> The answer above (worked math) will be unique per ISP. It will also >> >> drive >> >> consumption at the apex, i.e. the size of allocations to ISPs. >> >> >> >> And root of the problem was brought into existence by the insistence >> >> that >> >> every network (LAN) must be a /64. >> >> >> >> That's my 2 cents/observation. >> >> >> >> Brian >> > >> > At a glance, I think there's an implicit assumption in your >> > calculation that each ISP has to be able to hold the whole world >> > (unlikely) and/or there is no such thing as mobile IP or any other >> > kind of tunneling technology going on within the mobile network (also >> > wrong from everything I understand). >> > >> > Also, I'm not sure where "from the current /8" comes from, as there's >> > a /3 in play (1/8 of the total space, maybe that was it?) and each >> > RIR is getting space in chunks of /12... >> > >> > Re-working your conclusion statement without redoing the math, "This >> > leaves room for 2^15 such ISPs (a mere 16384), from the current /3." >> > >> > Oddly enough, I'm OK with that. :) >> >> 16384 'isp' which is really 'transit asn' right? > >