I'm sorry Mel, I only now saw your email. I'll quote from my reply to Owen, for the motivation behind my question:
> Speaking of IPv6's full potential: we're considering 32 subscriptions > per client. I've read people thinking of things like IPv6-aware soda > cans. Refrigerators. Wearables. Cars and their internal components... > You could have the on-board computer talking to the suspension via IPv6, > and reporting back to the manufacturer or whatnot. > > Personally, I'm not particularly fond of the whole "refrigerators > ordering milk bottles" craze, but hey, it may very well become a thing. > And other stuff we haven't thought of yet. > > My point is: we're changing to a brand new protocol, and only now > beginning to scratch its full potential. Yes, everything seems very big > right now. Yes, 128 bits can be enough. Even 64 bits could be more than > enough. But why limit ourselves? Someone decided (corretly) that 64 > would be too limiting. > > Please don't fall into the usual "you've got more addresses than > atoms"... I've heard that, and am not disputing it. I'm not just talking > about individual addresses (or /48's). > > What I am proposing here, as food for thought, is: what if we had e.g. > 192 bits, or 256? For one, we could have much sparser allocations. Heck, > we could even go as far as having a bit for each day of the month. What > would this be good for? I don't know. Perhaps someone may come up with a > use for it. > Regards, Israel On 07/09/2015 02:46 AM, Mel Beckman wrote: > Israel, > > A better question is why bit-map your allocation plan at all? That seems ill > advised, since you must arbitrarily allocate huge swaths of ip space equally > between category classes when it's rarely efficient to do so. For example, > two bits for network infrastructure because infrastructure addresses are > likely far fewer than any customer class. Similarly three bits for geographic > region on the /38 boundary illogically assumes all geographic regions are the > same size. > > There isn't a good routing reason for a bitwise address structure, since > nobody routes that way. The only other rationale I can think of is human > mnemonic value, but 128-bit addresses are not very amenable to such mnemonics > (::DEAD:BEEF not withstanding :) > > -mel beckman > >> On Jul 8, 2015, at 6:32 PM, Owen DeLong <o...@delong.com> wrote: >> >> >>> Let's say I'm a national ISP, using 2001:db8::/32. I divide it like so: >>> >>> - I reserve 1 bit for future allocation schemes, leaving me a /33; >>> - 2 bits for network type (infrastructure, residential, business, LTE): /35 >>> - 3 bits for geographic region, state, whatever: /38 >>> - 5 bits for PoP, or city: /43 >>> >>> This leaves me 5 bits for end sites: no joy. >> Here’s the problem… You started at the wrong end and worked in the wrong >> direction in your planning. >> >> Let’s say you’re a national ISP. Let’s say you want to support 4 levels of >> aggregation. >> Let’s say that at the lowest level (POP/City) you serve 50,000 end-sites in >> your largest POP/City. (16 bits) >> Let’s say you plan to max out at 32 POPs/Cities per region (your number from >> above) (5 bits) >> Let’s say you plan to divide the country into 8 regions (3 bits) >> Let’s say for some reason you want to break your aggregation along the lines >> of service class (infrastructure, residential, business) >> as your top level division (rarely a good idea, but I’ll go with it for >> now) and that you have 4 service classes (2 bits) >> Further, let’s say you decide to set aside half your address space for >> “future allocation schemes”. >> >> Each POP needs a /32. >> We can combine the Region/POP number into an 8-bit field — You need a /24 >> per Region. >> You need 3 additional bits for your higher level sub-divisions. Let’s round >> to a nibble boundary and give you a /20. >> >> With that /20, you can support up to 67 Million end sites in your first plan >> still leaving 3/4 of your address space fallow. >> >> (That’s at /48 per end-site, by the way). >> >> Now, let’s consider: 7 Billion People, each of which represents 32 different >> end-sites — 224 billion end-sites world wide. >> 224,000,000,000 / 67,000,000 = 3,344 (rounded up) total ISPs requiring /20s >> to serve every possible end-site on the >> planet. >> >> >> There are 1,048,576 /20s total, so after allocating all the ISPs in the >> world /20s, we still have 1,045,232 remaining. >> >> Let’s assume that every end-site goes with dual-address multi-homing (an >> IPv6 prefix from each provider). >> >> We are now left with only 1,041,888 /20s remaining. You still haven’t put a >> dent in it. >> >> Even if we divide by 8 and just consider the current /3 being allocated as >> global unicast, you still have 130,236 free /20s >> left. >> >>> Granted, this is just a silly example, and I don't have to divide my >>> address space like this. In fact, I really can't, unless I want to have >>> more than 32 customers per city. But I don't think it's a very >>> far-fetched example. >> It’s not… It’s a great example of how not to plan your address space in IPv6. >> >> However, if we repeat the same exercise in the correct direction, not only >> does each of your end-sites get a /48, you get the /20 you need in order to >> properly deploy your network. You get lots of space left over, and we still >> don’t make a dent in the IPv6 free pool. Everyone wins. >> >>> Perhaps I'm missing something obvious here, but it seems to me that it >>> would've been nice to have these kinds of possibilities, and more. It >>> seems counterintuitive, especially given the "IPv6 way of thinking" >>> which is normally encouraged: "stop counting beans, this isn't IPv4”. >> The problem is that you not only stopped counting beans, you stopped >> counting bean piles and you lost track of just how big the pile that you are >> making smaller piles from really is. >> >> I hope that this will show you a better way. >> >> Owen >>
