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

["Pascal Thubert (pthubert)" <[e-mail]>]

Hello Thomas and all:

We can achieve some mobility for best effort RPL routes, it is mostly a matter of tuning of the protocol and OF. The exact details on what is needed could be worked out at ROLL.
For us that would mean beef up the dynamic slot allocation that has to be there anyway.

OTOH, my memory is that we agreed that deterministic and mobile do not play well, not well at all for centralized routing. So I agree with Thomas that we should not over commit.
Maybe for the time being we could place that in the interaction with other WGs, ROLL in this case?

Cheers,

Pascal

From: [e-mail] [mailto:[e-mail]] On Behalf Of Thomas Watteyne
Sent: dimanche 21 juillet 2013 23:28
To: 6TSCH
Subject: Re: [6tsch] work item 2 in the charter

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]<mailto:[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]<mailto:[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]<mailto:[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