Le 31/03/2013 07:25, Fernando Gont a écrit :
On 03/30/2013 03:49 PM, Alexandru Petrescu wrote:
That said, IPv6 addresses identify network attachment points. If
you need semantics other than that ("e.g., distinguish between
past, current, and future vehicles"). my take is that you're
looking at the wrong place, possibly at the expense of nodes that
do the right thing.
I did't mean to say do distinguish between old and new vehicles by
using an IPv6 address.
I meant to say that this VIN mapping to an IPv6 address may be
useful not only to newly manufactured vehicles, but also to old
vehicles.
Why should a VIN map to an IPv6 address in the first place?
IMO, you should follow what appears to be the consensus on the
subject: set the IID in whatever way you want,
About this there is a tendency to agreement. The privacy aspect should
be considered, balanced by a privacy-to-mobility tradeoff.
But this VIN topic is also about how to generate an ULA prefix when no
EUI-64 is available. (if ULAs are good to be used in a vehicle).
as long as you don't expect others to use the same semantics as
yourself (or as long as you can gracefully handle the case in which
others do not employ the same semantics as you).
Ok.
Third-party vehicle equipment manufacturers (not those who
manufacture the vehicle itself) may manufacture and sell a Router
to be deployed in the vehicle, to connect the vehicle to the
Internet. This Router would be put in new vehicles but also in old
ones. (just like one may add e.g. rearview camera to a vehicle
which didnt have one at manufacture time).
This Router sold by the third-party needs to know what IPv6
addresses are or should there be in the vehicle.
Isn't this a case of network mobility?
YEs it is. Network mobility has a means to dynamically acquire a prefix
for the moving network, from the HA. But it doesnt say whether that
prefix could be used for direct vehicle-to-vehicle communications, or
shouldnt.
_If_ ULA space may be used then one wonders how to generate one
ULA prefix for one vehicle. The RFC ULA does suggest an example
algorithm, but it says other algorithms may be possible.
The idea is that the prefix is randomized, as to reduce colisions,
IIRC.
Yes, and it suggests an algorithm for doing so. That algorithm uses
EUI-64. Some MRs may have several such, or none. What to use in these
case?
Also, the example given has some uncertainties (whose interface
EUI-64 should be chosen?).
Not sure what you mean....
This is one reason we came to generating IPv6 prefixes, and
Interface IDs, out of VIN.
(it's maybe only me who sends too many emails on this topic, but it
is not only me and my co-authors of the mentioned drafts, but there
are other people at IETF worked on this VIN-IPv6 topic, presented
to f2f IETF meetings, and there exist some IPR activity in that
space as well).
I'm not arguing that you're the only guy working on this, nor that
this VIN->IPv6 mapping might be useful to those working on VIN-IPv6
topic -- I'm rather arguing that IPv6 address should be... IPv6
addresses
Yes. Precisely as IPv6 addresses are IPv6 addresses and sometimes
contain EUI-64 identifiers in clear.
(assuming you want IPv6 address to have any other semantics than
"point of attachment").
If your point is "We are not intending to introduce any additional
semantics to the IPv6 addresses/IIDs, but rather are not sure how we
should implement RFC XXXX in our specific case", please do let me
know, and I'll look further into this.
Provided that the use of ULA in a vehicle is acceptable, one would try
to find out how to generate a ULA prefix in a vehicle, and maybe on a
Mobile Router which has several EUI-64, or none.
Alex
Thanks,
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