Benjamin,

On 5/29/08, Benjamin A. Rolfe <[EMAIL PROTECTED]> wrote:
> Sorry, first post to the list, so forgive if I'm sounding like a newbie...
> How would one get link quality information to the upper layers other than
> via a MAC service?

We are in the same track. That's why I think we need to utilize
information from MAC for 6lowpan routing matrics.

> I can see inserting a shim-layer service to isolate upper layers form the
> different MACs which may be under it, so as to provide a consistent service
> interface. Of course you can only get what the MAC provides, but the shim
> layer and upper layer's can be designed to handle gracefully different MAC
> capabilities (at least consistently).
>

:)

> I'm asking with a bit of a bias here: I'm currently working on MAC
> enhancements for 802.15.4 (in task group "e" in 802.15), including a
> proposal for enhanced link assessment information from the MAC. So of course
> I'd suggest not ruling out some better link metrics in the 802.15.4 MAC at
> some point, although upper layers still need to deal with existing 802.15.4
> devices.  So the general thinking from upper layer uses is very interesting.
> Thanks
> -Ben
>

The current 6LoWPAN RR draft has been started with the reason you
concern, and we've kept working on it, as I believe that there are
necessity of this work nevertheless some folks have different
opinion(I'm trying to listen other side too).

Thank you for sharing your thought. :)

- eunah

>
> ----- Original Message -----
> From: "Eunsook "Eunah" Kim" <[EMAIL PROTECTED]>
> To: "Philip Levis" <[EMAIL PROTECTED]>
> Cc: <[EMAIL PROTECTED]>; <[email protected]>
> Sent: Wednesday, May 28, 2008 7:54 PM
> Subject: Re: [6lowpan] New charter for 6lowpan
>
>
> > Philip,
> > Thanks for the comment. LQI in the draft was mentioned for one
> > requirement, and it is given as just one of the examples for routing
> > matrics to utilize possible information to build up better routing
> > metrics for low power networks. If you think we shouldn't bond 6LoWPAN
> > to use MAC metrics, I'm okay with that. We can rule out it, but keep
> > doing the study about routing matrics. Thank you.
> >
> > -eunah
> >
> > On 5/29/08, Philip Levis <[EMAIL PROTECTED]> wrote:
> >>
> >> On May 28, 2008, at 1:04 AM, Eunsook Eunah Kim wrote:
> >>
> >> > Dear Philip,
> >> >
> >> >
> >> > > What happens when a new low power link layer emerges? Having N
> >> > > different solutions, each with their own details, which somehow need
> >> > > to be made to work well together, seems like a path of brittle and
> >> > > difficult to manage networks. Switches are good, to a point; there's
> >> > > a
> >> > > reason you have routers.
> >> > >
> >> > >
> >> >
> >> > We don't talk about solutions. We want to see if 6LoWPAN has special
> >> > routing requirements due to 802.15.4 specific or not. If route-over
> >> > solutions can be provided to fit the requirements of 6LoWPAN, I'm
> >> > happy.
> >> >
> >>
> >> Exactly: as soon as you start talking about things like LQI, you are
> >> coupling yourself not only to a specific link layer, but also a specific
> >> implementation of that link layer. In practice, many networks use the
> >> 802.15.4 link layer but not its MAC layer, as it has terrible energy
> >> properties.
> >>
> >> Phil
> >>
> > _______________________________________________
> > 6lowpan mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/6lowpan
> >
>
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