Arch Rock.
Jonathan, can you give detais?
Best,
Julien
________________________________
From: Colin O'Flynn [mailto:[email protected]]
Sent: mardi 13 octobre 2009 15:51
To: Julien Abeille (jabeille); '6lowpan'
Subject: RE: [6lowpan] Fundamental concerns about 6lowpan ND
Yes, but is Contiki a usable implementation for what we want to
do?
How well does sleeping or mesh routing work for instance? That
is what I mean by an implementation that uses full ND6 - someone doing
mesh + sleeping + RFC4861/2.
Regards,
-Colin
From: Julien Abeille (jabeille) [mailto:[email protected]]
Sent: October 13, 2009 2:23 PM
To: Colin O'Flynn; 6lowpan
Subject: RE: [6lowpan] Fundamental concerns about 6lowpan ND
Hi Colin,
any stack that passes IPv6 ready tests does, i know two of
these, one being Contiki/uipv6.
Best,
Julien
________________________________
From: Colin O'Flynn [mailto:[email protected]]
Sent: lundi 12 octobre 2009 18:46
To: Julien Abeille (jabeille); '6lowpan'
Subject: RE: [6lowpan] Fundamental concerns about
6lowpan ND
Hello,
I understand the problems with 'redesigning' a core IPv6
protocol.
However I'm curious about existing implementations that
use full IPv6 ND, do you have details?
I see the 6LoWPAN ND as a 'necessary evil', however I
would love to be proven wrong!
Regards,
-Colin
From: [email protected]
[mailto:[email protected]] On Behalf Of Julien Abeille (jabeille)
Sent: October 12, 2009 1:47 PM
To: 6lowpan
Subject: [6lowpan] Fundamental concerns about 6lowpan ND
Dear WG,
I have serious concerns about the 6lowpan ND draft and
would like to have the WG opinion on this. I agree that a few issues
arise in lowpan environments, which are mostly linked to the non
transitivity of some link layers used in lowpans. However, my two major
points of concern are:
- RFC4861 and RFC4862, which are core to IPv6, are being
very heavily redesigned. I believe that the proposal if it is done in
6lowpan MUST be designed as an optional extension to ND, not a redesign.
The charter states that the draft should propose "optimizations" and
"limited extensions" to ND. It is not the case at the moment. The proxy
ND proposal, the mandatory addressing model proposed, also goes beyond
the scope of the document as spelled out in the charter.
- non transitivity is not a lowpan only issue, hence if
adaptations to ND must be done, it should be in another WG, probably
6man
If these two points are not respected,
- it questions the applicability of IPv6 in smart object
networks: the draft is redesigning roughly 80% of RFC4861 and RFC4862,
which are core to IPv6
- existing IPv6 implementations will be strongly
impacted, as a number of major components will have to become layer 2
dependant:
-- address resolution will have to be disabled
-- DAD will have to be modified
-- NUD will have to be modified
-- prefix discovery will have to be modified
-- autoconf will have to be modified
-- IPv6 addresses will not be configurable if their IID
is not based on the MAC address
-- ... all these changes are 6lowpan dependant, as they
do not impact traditional links. This will raise important
interoperability issues.
- new layer 3 protocol designs will become layer 2
dependant. This is what is currently happenning in the ROLL WG by
proposing to use a different message to transport routing information,
depending on the medium.
Moreover, a number of existing deployments show that the
issues arised on lowpan networks as far as ND is concerned are not huge:
the deployments work, and ND as it is has proven to be power consumption
friendly. DAD is the most problematic procedure, that requires work, as
two hop neighbors do not see NS sent for DAD (see at the bottom)
In conclusion, I believe the advantages of rebuilding
neighbor discovery for lowpans are by far inferior to those of keeping
using the "same IP" on all medium. If some redesign has to be done, it
MUST be done in a more general fashion, probably in 6man, and in a much
lighter way.
Best,
Julien
DAD issue description:
node A and node C see node B, but not each other. nodes
A and B boot, configure a link local address, perfom traditional DAD. It
works. Node C boots with the same MAC address than A, configures the
same IP address, sends a NS to perform traditional DAD. A does not see
the NS hence C address configuration works. A and C have the same
address. B will not differentiate A and
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