Re: [6tsch] work item 2 in the charter

[Thomas Watteyne <[e-mail]>]

Qin, all,

We've had a lot of discussion around mobility during the webex calls a
couple of months ago. I'm looking at the call from 3/22 in particular, the
minutes of which are at [1] and the recording at [2].

We ended up identifying 2 cases where some nodes are mobile:
- nodes mounted on a crane. Either the crane is pivoting, or two cranes
cooperate to pick containers up.
- a mobile worker

We agreed that there were a number of tricks we could play to accommodate
some mobility:
- for the crane case, Alfredo suggested that we could "have [the] same
cells scheduled at several potential neighbors of the node mounted on the
crane"
- for the mobile worker case, Tom suggested that "mobile worker does not
require deterministic schedules".

In light of that, I would like to suggest to not over-promise on mobility.
That is, we think we have a good solution for building static network, and
that there are some tricks we can play for making space for some mobility.
Yet, the solution we come up with involve some communication to resolve
topological changes, either with a PCE, or locally using some reservation
protocol. Since there is some delay/overhead associated with that, they are
not designed for e.g. swarms of mobile robots. I'm not saying TSCH is not a
good idea for swarms of robot, rather that we first focus on (almost)
static networks.

Maybe I'm missing your point. If I am, could you write down the exact
rewording of the charter you are suggesting, and maybe point out the exact
use cases?

Thanks,
Thomas

[1] https://bitbucket.org/6tsch/meetings/wiki/130322_webex
[2]
https://cisco.webex.com/ciscosales/lsr.php?AT=pb&SP=MC&rID=66940742&rKey=711b58d40cd574d9

On Sunday, July 21, 2013, Qin Wang wrote:

> Pascal,
>
> Yes, I think we can add "mobility" in the first paragraph of "Description
> of Working Group [2/5]".
>
> Thanks
> Qin
>
>
> On Sat, Jul 20, 2013 at 2:55 PM, Pascal Thubert (pthubert) <
> [e-mail]> wrote:
>
>  Dear Qin:****
>
> ** **
>
> I’m a bit out of sync.****
>
> ** **
>
> 1) I agree we shoud have mobility somewhrere****
>
> 2) slide 8 in the charter slides on the repo is this “ Description of
> Working Group [2/5]”****
>
> ** **
>
> Is that where you’d like to see mobility mentioned?****
>
> ** **
>
> Cheers,****
>
> ** **
>
> Pascal****
>
> ** **
>
> *From:* Qin Wang [mailto:[e-mail]]
> *Sent:* vendredi 19 juillet 2013 21:12
> *To:* Pascal Thubert (pthubert)
> *Cc:* [e-mail]
> *Subject:* Re: [6tsch] work item 2 in the charter****
>
> ** **
>
> Hi Pascal,****
>
> ** **
>
> The slides are pretty good. Just a comment on slide-8. Should we add
> "mobility" as one of criteria?****
>
> ** **
>
> Thanks****
>
> Qin****
>
> ** **
>
> ** **
>
> ** **
>
> ** **
>
> ** **
>
> ** **
>
> On Sat, Jul 20, 2013 at 12:06 AM, Pascal Thubert (pthubert) <
> [e-mail]> wrote:****
>
> Dear all:****
>
>  ****
>
> Please review the latest draft of the charter at
> https://bitbucket.org/6tsch/charter-ietf-6tsch/src ****
>
> Now is a good time to find the bugs! ****
>
> Work Item 2 in the charter (
> https://bitbucket.org/6tsch/charter-ietf-6tsch/) is still like this:****
>
>  ****
>
> “****
>
> 2. Produce "6TSCH centrali
>
>