Alexandru, On Mar 28, 2013, at 9:37 AM, Alexandru Petrescu <alexandru.petre...@gmail.com> wrote:
> Sorry for the late reply. > > Le 19/02/2013 22:08, joel jaeggli a écrit : >> On 2/19/13 12:40 PM, Alexandru Petrescu wrote: >>> >>> >>> I think I may need to actually better expose the problem: how to form >>> IPv6 addresses for vehicles. (yes we know these already exist: DHPCv6, >>> PRefix Delegation on cellular, stateless autoconf, NAT, NPT, 64share). >>> >> One of the questions I have in that context what special property of >> cars make them need a new method? > > Well they're different than Ethernet interfaces. One could have several > Ethernet interfaces in a single car. And, cars have their globally unique > space of identifiers which is not EUI-48. > > When one tries to make an IPv6 addressing architecture for vehicles one goes > into planning which could quickly overcome the space of IPv6. > > There are very many hurdles to a simple straightforward IPv6 address planning > for vehicles. > > 1 - At most 2^78 vehicles may exist. That's a lot of vehicles. It is 302,231,454,903,657,000,000,000 to be exact. The current world population is currently a little over 7 billion (7,075,000,000). Assuming a few orders of magnitude of population growth and ownership of multiple vehicles per person, that still much much much smaller than 2^78. I don't we need to worry about handling 2^78 vehicles. Where does that number come from? > > There may be not enough space in IPv6 addressing architecture space > to uniquely distinguish between all past current and future > vehicles. > Likewise, I don't think we need to deal with past vehicles. We do need to deal with the active vehicles that are likely to be on the Internet. Bob > Theoretically, the total number of vehicles possible is given by > interpreting the semantics of VIN (17 "digits", some holding > max 33 values, others less). Under optimistic interpretations, a > trivial 1-to-1 conversion from VIN "characters" space to bit-space > of an IPv6 address leads to 78bits. > > (the structure of VIN is : > 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 > +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ > | WMI | VDS | VIS | > +--------+-----------------+-----------------------+ > but more details on the net searching Vehicle Identification > Numbers) > > It's hard to imagine that the first 78 bits of an IPv6 address > designate one particular vehicle. The IPv6 address structure > ofers something like a maximum of 61bits to designate one > particular subnet. And, in a vehicle there is often more than one > subnet. > > 2 - the prefixes obtained from Registries, or from ISP (which one > should I try first?) may come with a price tag. The more vehicles, > the pricier the allocation. > > 3 - prefixes which are provider-assigned and/or provider independent > may introduce routing churn in the core of the Internet - if these > prefixes are numerous. > > For these reasons, we still look closely at the use of ULAs (instead of > globally routable prefixes) and at how to generate these ULAs meaningfully. > > Alex > >>> Alex >>> >>>> >>>> Doug >>>> >>>> -------------------------------------------------------------------- >>>> IETF IPv6 working group mailing list ipv6@ietf.org Administrative >>>> Requests: https://www.ietf.org/mailman/listinfo/ipv6 >>>> -------------------------------------------------------------------- >>>> >>> >>> -------------------------------------------------------------------- >>> IETF IPv6 working group mailing list >>> ipv6@ietf.org >>> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 >>> -------------------------------------------------------------------- >>> >> >> >> > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
