Hi Jeroen, On 27.09.2011 17:55, Jeroen Massar wrote: > On 2011-09-27 17:36 , Rob V wrote: >> That doesn't mean all the systems within the car need to speak to the >> outside world. The engine thermometer doesn't care about traffic or the >> location of the nearest train station. It just needs to tell the dashboard >> its current read-out. I presume those are the kinds of systems the OP was >> referring to. > > And thus those systems likely will communicate inside a closed network > only and will not ever have to talk to another such system
Yes, at least not with the internal addresses. For other scenarios than car onboard networks, different networks may be visible at the same time in the future, e.g., formerly independent sensor networks get used together in a bigger scenario. > As such, what is simply wrong with hardcoding a single ULA /48 prefix in > all those systems? Maybe this works in a car scenario, but addresses may leak or formerly isolated and independent networks get coupled in other scenarios and then it's good to have unique address prefixes. > The moment that something is going to talk to them, there will be a > interface/system/proxy involved which will sit on both networks anyway. In this particular scenario, yes. > Unless the mechanic at the garage can figure out which prefix is being > used inside the car and has a system that can set up proper routing in > and out of that block. Or the other way that his host is going to get an > interface connected to that network and takes an address out of that prefix. Yep. > I guess as we are all guessing here what the system is, the better > question is: where is the proposed design of how this system is going to > look like and what it's requirements truly are. I have to check with the consortium first, whether I can provide more details on this. > Saying "I need ULA" is coming up with a solution without looking at the > actual problem at hand. I'm not saying that ULAs are the only solution, but ULAs seemed to be be a good fit for the problem. If global addresses can be easily used unconnected, one may use these, see below. > That said though, every single case of ULA-C will end up the same as the > address space that RIRs are already distributing: globally unique. > Thus from that perspective there is already perfect ULA-C. I wasn't sure that the RIR policies allow that use. Aside from the well-known prefix of ULAs, the difference isn't that large. Regards, Roland -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
