On Nov 3, 2012, at 19:25 , Alexandru Petrescu <alexandru.petre...@gmail.com> wrote:
> Le 03/11/2012 18:54, Romain KUNTZ a écrit : >> Hello Alex, >> >> On Nov 3, 2012, at 17:41 , Alexandru Petrescu >> <alexandru.petre...@gmail.com> wrote: >> >>> Le 25/10/2012 15:52, Michael Richardson a écrit : >>>> >>>> ralph> Why wouldn't RPL be used for such networks? It has >>>> built-in PD for ralph> dynamic networks, if I understand it >>>> correctly, with RA used at the ralph> subnet level. >>>> >>>> Alexandru Petrescu <alexandru.petre...@gmail.com> wrote: AP> RA >>>> used to exchange routes - if this is what you mean, and yes it >>>> may be AP> used by RPL (last time I read it). >>>> >>>> AP> If the question is about this, then I think it is pertinent. >>>> One may AP> imagine a way to use RPL on the MRs for that >>>> purpose. >>>> >>>> AP> However, I doubt RPL can Delegate Prefixes (in the pure >>>> sense of Prefix AP> Delegation). >>>> >>>> RPL doesn't do this in protocol, but then, neither does ND. I >>>> wouldn't extend RPL to do this, however, I'd send a DHCPv6 PD >>>> format message. It can be a single exchange, and nobody said a >>>> single program can't speak multiple protocols. >>> >>> Yes, but consider that DHCPv6-PD is already used in a rather >>> complicated way on the MR of an IV (Internet Vehicle). It is used >>> according to rfc6276, to obtain a prefix from home. In that it is >>> specified that MR should be both a Requesting Router and a Relay >>> for that tunnel interface. >>> >>> On another hand, if the MR of LV requests a Prefix from the IV's >>> MR then this latter should also be a Relay, but on a real interface >>> as well. >>> >>> One ends up with two Relay software on the same machine. I am >>> afraid this is next to impossible to configure with some existing >>> software. >> >> Why two Relays? I believe one relay listening to multiple interface >> is enough. > > Yes, a Relay I guess could listen on two interfaces (to be checked?). >From what I understand, RFC3315 does not forbid it. > But I mean the Relay's interface towards the other end, the one towards > the Server. I think, if I'm not wrong, that's only one interface > possible. MIP-NEMO-DHCP-PD would use it to talk to HA. > > The MR-IV would need this additional Relay's interface towards the > immediate fixed infrastructure (not the remote tunnelled HA). In the > case one would want direct IV-LV communications without HA. In the scenario from your draft, it seems that the DHCPv6 server that delegates prefix to the MR-IV and to the MR-LV is the same, so why would that interface be different? In both cases the DHCPv6 messages would go through the MR-IV - HA tunnel, or did I miss something? But even you use different interfaces, I believe nothing prevent a DHCPv6 relay to do so. There is no considerations on the number of interfaces to send/receive messages in RFC3315. Sending or relaying messages to a server is just a matter of knowing the server address and having a route for it. Before discussing solutions, I think there are probably a number of questions to answer about the ITS scenarios. For example, would the DHCPv6 server delegating prefixes for the MR-IV and the MR-LV be the same or not? Each would probably belong to the provider affiliated with the vehicle. Thank you, Romain > I may be wrong though about Relays' capabilities. It just that it looks > complex to me to set up, rather than using ND on the link between IV and > LV looks simpler. > > Alex > >> >> Romain >> >>>> But, I question whether one always needs to get address space, vs >>>> announce it. I don't know the answer: it really depends upon who >>>> your second vehicle needs to talk to, and why it thinks that >>>> vehicle one (and vehicle one's ISP) is willing to give it >>>> bandwidth. >>> >>> I think both tools of announcing address space, and obtaining >>> address space, should be available to vehicles, and applied >>> depending on whether the communication is between two vehicle >>> devices only, or not, whether the infrastructure is available, or >>> not. >>> >>> It is viable that an LV self-configures ULAs based on VIN and >>> announces them only to vehicles nearby (not to infrastructure). >>> >>> It is viable that an LV to get globally routable address space >>> from an IV. >>> >>>> If you don't want to speak RPL, then you need to pick the TBD >>>> homenet-routing-protocol. We don't need a third. >>> >>> Needing a third or not - I don't know. But picking homenet >>> protocol, or RPL for vehicles would probably involve a large >>> change in requirements of either. >>> >>> Alex >>> >>>> >>> >>> >>> -------------------------------------------------------------------- >>> >>> >>> > 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 --------------------------------------------------------------------
