Many thanks to John for his post. Yes, what is the problem we are trying to solve here ? With NEMO, there is no problem related to changing IP addresses ? NEMO is the solution for that. The in-vehicle router would still get a new CoA while in the in-vehicle nodes would keep the prefix initially allocated. This is the solution adopted by ISO TC204 (technical committee working on ITS), see the published standard ISO 21210. This is also what is being experimented in ITS field operational tests.
Of course, with a solution like NEMO the route is not optimized, but the scenarios currently being considered for deployment from the automotive industry wouldn't require direct routing between two vehicles nor would require optimized routing between a vehicle and a correspondent in the Internet. The scenarios where we really need direct communications are when an in-vehicle node need to speak with a roadside node that is attached to the access router. Other scenarios depicted by Alexandru are good for research.
For the scenario involving the roadside and the vehicle, the prefix can be exchanged as proposed by Lee (draft-jhlee-mext-mnpp). The solution from Lee is being integrated in the ISO TC204 standards related to ISO 21210.
Regards, Thierry. On 24/10/12 02:56, John Mann wrote:
Hi,On 23 October 2012 03:54, Alexandru Petrescu <alexandru.petre...@gmail.com <mailto:alexandru.petre...@gmail.com>> wrote:Le 20/10/2012 23:51, Thierry Ernst a écrit : Dear Alex, Would you explain why the vehicle would need to get a new prefix (and thus I assume configure all the nodes in the vehicle) every time it enters a new area ? Well, whenever MR of a vehicle changes its attachment point it would get a new different address, right? I can only suppose it would get a different delegated prefix as well. It's hard to imagine that it would get a different address but a same delegated prefix, no? (it's hard to make same prefix valid at so many different places, harder than doing it with addresses and it's not done with them). Or do you ask why LV gets a new prefix when IV changes its prefix? I think this is obvious, no? (for topological correctness, right?) Or do you ask from the NEMO perspective? In this V2V2I work we first consider there's no MIP nor NEMO neither on IV nor on LV. We'll see later about adding MIP. We can discuss it as well, see how MIP would fit in this. Is this answering in the direction you made the question? Alex I'm confused about what problems are being solved / created here. I assume V2V2I is vehicle-to-vehicle-to-Internet.Why do you _want_ the LFN end devices to change IPv6 address as the vehicles move around?How about if you one-off assign prefixes to the in-car subnets, and then one-off assign host addresses to the LFNs. Then use tunnels / NEMO / Proxy MIPv6 / whatever to connect the cars to the Internet. The LFNs having stable addresses would facilitate connections to and from the Internet.Is there some soft of association between IVs and LVs? - are they owned / managed by the same people? - is there guaranteed to always be a IV in range of every LV?- are the IV's happy that the LVs are using their bandwidth to the Internet? - is there any need for the LFNs on IVs and LVs to communicate with each other? locally? Do e.g. cellular or satellite networks used for connecting IVs to the Internet give out different IPv6 address or delegate different prefixes as you move around?Or does it take a roam plus a "reboot" to get a new address and prefix? Thanks, John Thierry On 20/10/12 20:10, Alexandru Petrescu wrote: Le 20/10/2012 18:42, Mikael Abrahamsson a écrit : On Sat, 20 Oct 2012, Alexandru Petrescu wrote: One point that guided towards choosing ND over DHCP is topology. DHCP topology can be relatively complex with Client/Relay/Server, whereas ND is simpler one-on-one. There is nothing saying DHCPv6-PD can't be done in a single device (the router itself). That's what I do in my home, cisco router, local DHCPv6-PD pool, local DHCPv6-PD server, also installing routes into RIB. YEs, because at home one typically puts up the interface once a month and gets typically the same prefix from ADSL operator as 1 year before. But with vehicles, one connects a vehicle here and gets a prefix, then moves in that area and gets another prefix. At that point, if the router obtaining a prefix wants to delegate further to another vehicle needs to change the delegated prefix. This dynamic change between the received prefix and the delegated prefix is not a matter of DHCP. It can be implemented by like scripting which are independent of DHCP implementation. One has to touch the conf files be it of DHCP or of ND. _and_ Relay (or Server). This may be feasible in practice but I think it would be cleaner to have distinct protocols on a same machine for receiving a prefix and for sending a prefix. What is cleaner is to use existing standards where there already is running code. Right, there is cleanliness in reuse. Reuse as much as possible. There is also the question of availability of DHCP software on smaller platforms which have no SIM card. It may be easier to do this with ND in smaller settings. I'd imagine that there already are 2-3 existing FOSS available implementations that do what you need for DHCPv6-PD client and server. Instead you want to invent a new standard and create new code. In addition to FOSS (what is FOSS?) DHCP one also needs to dynamically change the delegated prefix when the assigned prefix changed. I'm not saying this shouldn't be done, I'm just saying I don't really see the rationale for it. I used to hate DHCPv6 role in IPv6, but after a few years of being exposed to it, I've come to accept that this is the way it is. There is code going back to a standard Windows Vista that correctly implements DHCPv6-PD client, and that is what, 5-6 years ago it was released? I've had PD in my home on Cisco code for 3-5 years already, with no server infrastructure at all, just single device doing "everything" for the role needed. If this was 2002, I'd agree with you that ND PD could be feasable, but I believe the train has already left the station and we should focus on keeping IPv6 stable when it comes to how it works, and get implementations going, not new standards. WEll yes, I agree that IPv6 should be kept stable and part of that may be that we try to make sure that a new proposal does not break existing implementation. This is a matter of further work. 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