Re: Bluetooth 6LoWPAN and routing

[Alexander Aring <alex.aring@gmail.com>]

On Mon, Nov 04, 2013 at 07:46:06PM -0200, Claudio Takahasi wrote:
> Hi Jukka,
> 
> On Thu, Oct 24, 2013 at 9:48 AM, Jukka Rissanen
> <jukka.rissanen@linux.intel.com> wrote:
> > Hi Alexander,
> >
> >
> > On 24.10.2013 15:25, Alexander Aring wrote:
> >>
> >> Hi Jukka,
> >>
> >> On Thu, Oct 24, 2013 at 09:45:40AM +0300, Jukka Rissanen wrote:
> >>>
> >>> Hi,
> >>>
> >>> I have been prototyping with BT 6LoWPAN support (using this draft
> >>> http://tools.ietf.org/html/draft-ietf-6lowpan-btle-12 as a
> >>> reference). I sent first version yesterday to linux-bluetooth ml
> >>> http://thread.gmane.org/gmane.linux.bluez.kernel/39394
> >>>
> >> I see you take many code from the 6lowpan ieee802154 implementation.
> >> (Just notice you drop the original authors from there)
> >
> >
> > Hmm, those got dropped, I am sorry about that. I will add the original
> > authors information of course.
> >
> >
> >>
> >> I have a couple of patches to fix a lot of bugs in the current 6LoWPAN
> >> ieee802154 implementation.
> >>
> >> Some bugs which I found:
> >>
> >>    - Fix race conditions in fragmentation handling
> >>    - Fix UDP compression/uncompressionm, which is completly broken
> >>    - Fragmentation handling isn't rfc4944 compatible
> >>
> >> And some other improvements. I see your rfc has the same issues (e.g.
> >> fragmentation race conditions).
> >>
> >> Currently I preparing these patches for mainlining.
> >
> >
> > Excellent news!
> 
> 
> Is it necessary to implement 6loWPAN fragmentation/reassembling? For
> Bluetooth, I thought L2CAP FAR (Fragmentation and Reassembling) could
> handle the transfer of IPv6 packets that doesn't fit in one single
> BTLE PDU.
> What am I missing here?
>
mhh, I look a little bit deeper in the 6LoWPAN bluetooth draft and indeed
it can be handled via L2CAP FAR. I saw the fragmentation struct in the
rfc implementation(struct lowpan_fragment) but it isn't used in any case
so Jukka can drop this from the rfc implementation. Sorry about that.

But I don't see udp compression/uncompression in Jukka's rfc
implementation. But this is a part of rfc 6282 which should blte 6LoWPAN
should use?

So the 6LoWPAN fragmentation thing (rfc4944) is only ieee802154 specific.

- Alex