Re: [MEXT] Comments on draft-ietf-mext-nemo-ro-automotive-req-02.txt
Roberto Baldessari <Roberto.Baldessari <at> nw.neclab.eu>
2009-02-16 17:12:11 GMT
Thanks for your comments, please see inline.
> Thanks for this new version of the draft, and for having included some
> of my earlier comments.
> I think there is more to which we seemed to agree.
Yes, but it was not possible to apply all of the changes for the reasons you'll find below.
> > o according to the current availability of infrastructure
> > connectivity, OBUs can use (at least) 2 types of globally routable
> > IPv6 addresses: an IPv6 address configured using standard IPv6
> > stateless address configuration from Router Advertisements sent by
> > RSUs connected to a network infrastructure and an IPv6 address
> > temporarily or permanently assigned to the vehicle belonging to a
> > home network and not varying while the vehicle changes its point-
> > of-attachment to the Internet. The former globally routable IPv6
> > address is used as the NEMO Care-of Address (CoA) and the latter as
> > the NEMO Home Address (HoA).
> Sounds as if the HoA is not globally routable - it is.
Was not intended. We can repeat 'globally routable', if this makes things clearer.
> "IPv6 address assigned to the vehicle belonging to a home network" -
> belongs to the home network?
Obviously the address belongs to the network. Maybe this paragraph can be split into more sentences. We'll
try to clarify it.
> > o for V2V communication, i.e. when no infrastructure is available,
> > OBUs can use link-local addresses.
> This is only half useful. Only the OBUs can communicate to each other
> using their link-local addresses, on their egress interfaces. AUs in
> the vehicles can not take advantage of that, can not communicate to
> other. It sounds as a tempting method but deceiving in the end. (OBU:
> On-Board Unit, like an MR; AU: Application Unit, like an LFN).
> I think that should be mentioned.
Yes, we'll probably add it. Link-local addresses are listed in the section you mentioned because the list
is not restricted to those addresses that only allow AU-to-AU communication (in different mobile
networks). The subsection where this list is inform on IPv6 deployment and goes beyond the scope of NEMO
requirements. But adding an observation might be a good idea.
> In all cases, it shouldn't lead to application-level gateways.
> About Figures.
> Figure 1 and Figure 3 in 02 are the same as in 01, respectively - they
> haven't changed. Yet they're remarkably similar. What are the
> differences between Figure 1 and Figure 3? Why should they be
You're right about the figures and there was the intention to remove the duplication. But since efforts to
come up with a single architectural view are ongoing between ISO, C2C, ETSI and IEEE, we thought that it
would make more sense to have one single section describing a sort of harmonized architecture and move the
deployment-specific differences in an appendix, as soon as a stable draft is available.
> > [IEEE.802-11p-d3-0]
> The one I'm aware exists is D5.0 of November 2008. There may be other
> more recent?
Correct, D5.0 is the latest. We'll need to review the references and add ISO, ETSI stable drafts as soon as
they are ready.