Re: [ipwave] which BSM?

[William Whyte <[e-mail]>]

But none of that explains why the BSM type is in scope for this group. That
seems like a different work item.

- sent from my phone

On Tue, Apr 16, 2019, 12:28 PM Alexandre Petrescu <
[e-mail]> wrote:

>
>
> Le 16/04/2019 à 12:12, William Whyte a écrit :
> > That's a decision made further up the stack. It's not part of the scope
> > of this group.
> >
> > For what it's worth: In the US, the BSM-based applications are based on
> > SAE J2945/1 and SAE J2735-2016 and sent over WSMP. In Europe,
> > cooperative awareness using CAM is based on EN 302 637-2 and sent over
> > BTP. But even if BSMs were sent over IP, the version of BSM used would
> > be out of scope for this group. That's how layered systems work.
>
> I agree layered systems are good to focus, and interfaces.
>
> I think that an overarching CAM-BSM message put on UDP/IP specified at
> IETF may get benefits beyond just layering and interfaces.
>
> Such a spec would tell, for example, that in worst case the cars MUST
> accept both EtherTypes (dont drop either), by the principle of being
> conservative on what to accept.  And in best case expect an IPv6
> EtherType that carrying an IP datagram carrying an overarching BSM-CAM.
>
> That could probably improve safety in some situations.
>
> It is also true that that is a standpoint of IP packets being the same
> all over the world, whereas cars are not really the same.  E.g. in
> America the cars are allowed to have both left and right yellow lights
> turned on permanently, but not in other parts of the world.
>
> So I am really not sure whether an idea of an overarching CAM-BSM over
> IP can ever fly, even though I like it.
>
> Alex
>
> >
> > William
> >
> > - sent from my phone
> >
> > On Tue, Apr 16, 2019, 11:45 AM Alexandre Petrescu
> > <[e-mail] <mailto:[e-mail]>>
> wrote:
> >
> >     Which network/transport do BSMs use?
> >
> >     Alex
> >
> >     Le 16/04/2019 à 11:40, William Whyte a écrit :
> >      > I don't fully understand why IPWAVE, which is about network /
> >     transport
> >      > protocols, needs to have an opinion about what form of BSM to use.
> >      >
> >      > Cheers,
> >      >
> >      > William
> >      >
> >      > On Tue, Apr 16, 2019 at 10:58 AM Alexandre Petrescu
> >      > <[e-mail]
> >     <mailto:[e-mail]>
> >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>> wrote:
> >      >
> >      >     Sri,
> >      >
> >      >     Thank you very much for the email.
> >      >
> >      >     I would like to take this opportunity to discuss publicly a
> >     particular
> >      >     topic in your email, that we already touched upon in private
> >     a few
> >      >     months ago.
> >      >
> >      >     I purposefully keep the other ideas of you out of this email,
> >     but I do
> >      >     agree with very many of them.
> >      >
> >      >     Le 16/04/2019 à 05:11, Sri Gundavelli (sgundave) a écrit :
> >      >     [...]
> >      >      > From the point of view of vehicular safety, its about
> >     exchange of
> >      >      > BSM (Basic Safety Messages) between vehicles as per SAEJ735
> >      >      > standard.
> >      >
> >      >     Sri, but there are at least three versions of BSM.
> >      >
> >      >     Which BSM do you mean?
> >      >
> >      >     Why SAE and not ISO?  Both have 'International' in their
> names.
> >      >
> >      >     Why SAE 2016 and not SAE 2009?
> >      >
> >      >     - SAEJ2735 version 2009 (free access),
> >      >         (google hits "SAE J2735")
> >      >     - SAEJ2735 version 2016 (paid access, cca 100 USD),
> >      >         (google hits "SAE J2735")
> >      >     - and the ISO/CEN/ETSI versions (free access):
> >      > https://www.tc278.eu/cits
> >      > https://standards.iso.org/iso/ts/19091/addgrp_c
> >      >
> >      >     (remark I dont mention ETSI CAM, which is ITS safety in
> Europe).
> >      >
> >      >     The three seem to be different in contents, to a few people.
> >     Myself I
> >      >     identified the first and second to be distinct.
> >      >
> >      >     Ideally, safety would be just one standard, right?  Something
> >     like a
> >      >     combination of all BSM versions with the CAM version running
> on a
> >      >     transport that is common to all.
> >      >
> >      >     A safe car would need to be able to understand all these CAM
> >     and BSM
> >      >     versions; if it misses just one because of some syntax error,
> >     well,
> >      >     safety would be at stake.
> >      >
> >      >      > [...] and for very good reason IEEE WAVE standards did not
> >     bother to
> >      >      > require IPv6 transport for carrying these messages.
> >      >
> >      >     I doubt that reason.
> >      >
> >      >     Alex
> >      >
> >      >     _______________________________________________
> >      >     its mailing list
> >      > [e-mail] <mailto:[e-mail]> <mailto:[e-mail]
> >     <mailto:[e-mail]>>
> >      > https://www.ietf.org/mailman/listinfo/its
> >      >
> >      >
> >      >
> >      > --
> >      >
> >      > ---
> >      >
> >      > I may have sent this email out of office hours. I never expect a
> >      > response outside yours.
> >
>