Re: [6tisch] call for review: draft-ietf-6tisch-msf-04

[Esteban Municio <[e-mail]>]

Hi Tengfei,

I like the new changes, especially the concept of autonomous cells by
demand and always having by default 1 downlink negotiated cell. 

Here are some minor comments (checking msf-05):

* In Section 5.2, it is not clear for me if the parent switch occurs
before, during or after the 3-step procedure. My intuition says that is
should be after point 2: "the node triggers one or more 6P ADD commands
...". I guess it may be interesting to clarify when the actual parent
switch occurs.

* Also in the same section 5.2, it could be convenient (although maybe
redundant) to say in point 2 that the node has to schedule the same
number "and options" of negotiated cells. This would keep also the
ratio TX/RX with the new parent.

* Maybe out of the scope but, should not be defined here a housekeeping
function that removes unused negotiated cells (TX or RX)? For example
for cells that can't be removed with a 6P transaction (e.g. nodes are
not in range any more).

And some minor edit comments:

- "increaase"
- two "AutoUpCells" are still there
- two "managed unicast cell" are still there
- "it is possible for negotiated cell to avoid the collision with
AutoRxCell." Maybe "for a negotiated"?
- "For burst traffic type, larger value of MAX_NUMCELLS indeed
introduces higher latency." Maybe "a larger value"?

Kind regards,
Esteban

On Tue, 2019-07-02 at 12:57 +0200, Tengfei Chang wrote:
> Dear all,
> 
> As you may noticed that a new version of MSF is just published at
> here:
> https://tools.ietf.org/html/draft-ietf-6tisch-msf-04  
> There are some moderate changes comparing to previous one.
> 
> Mainly in two aspects:
> 
> 1. change the concept of autonomous cell
> 
> In the new version, there will be two type of autonomous cells:
> - autoTxCell, which is scheduled on demand for just transmitting
> -autoTxCell, which is schedule permanently, for just receiving
> (the previous version the autonomous cell are used as bidirectional)
> 
> More details about how to use those autonomous cell is available in
> the draft.
> 
> 2. re-added the downstream traffic adaptation feature
> 
> Though, there are cases that the node doesn't receive packet because
> of collision, we assume the influence won't be much to adapt the
> downstream traffic.
> We will evaluate the performance of this changes.
> 
> We are targeting to have a new version before the submission
> deadline.
> During the time, we will evaluate the v4 MSF and would like to have
> your comments as well.
> 
> Thanks in advance!
> 
> Tengfei
> 
> -- 
> Chang Tengfei,
> Postdoctoral Research Engineer, Inria
-- 
Esteban Municio
PhD Researcher, IDLab, University of Antwerp, in collaboration with
imec
[e-mail]
The Beacon | Sint-Pietersvliet 7 | 2000 Antwerpen, Belgium