Subject: [6tisch] #28 (architecture): Review by Randy Turner

From: "6tisch issue tracker" <[email-masked]>
Date: Tue, 21 Oct 2014 12:31:27 -0000

#28: Review by Randy Turner

 Section 6.2 "To broadcast ICMPv6 control messages used by RPL such as DIO
 and DAO.."  - I thought DAOs were always unicast towards the root ?
 [PT] That would be for RPL section 9.10. Multicast Destination
 Advertisement Messages

 Section 6.3  "A node that has joined the TSGI advertises a MAC level join
 priority set to its DAGRank() in that instance"  I think join priority is
 an 8-bit quantity,  DAGRank() I think is a 16-bit quantity - do we just
 mask with 0x00FF ?
 [PT] RPL defines
               DAGRank(rank) = floor(rank/MinHopRankIncrease)
   With a MinHopRankIncrease that is a multiple of 256, DagRank() fits in
 one octet. There was a catch about the size of the priority but it seems
 that we are fine using effectively all the 8 bits.

 Section 6.4 "In order to ensure that the medium  "if" free of contending
 packets when time..." s/if/is
 [PT] fixed 

 Section 6.4 "..so as to optimize the chances of interferences from
 slotted-aloha operations" - should "optimize the chances" be "minimize the
 chance" ?
 [PT] Maybe reduce?

 Section 6.4  "There is typically one slotFrame for scheduled traffic that
 has the highest precedence and one or more slotFrames for RPL traffic" --
 Does this imply two levels of packet precedence? High and "Best Effort" ?
 I'm assuming expedited forwarding (EF) marked packets would be assigned to
 the high-precedence slotFrame? Any suggestions here about how to map DSCP
 codepoints to SlotFrames ?
 [PT] That’s http://tools.ietf.org/id/draft-svshah-tsvwg-deterministic-
 forwarding-00.txt see section 9.1. Packet Marking and Handling

 Section 6.5  s/fulfil/fulfill
 [PT] fixed

 Section 6.5 "The 6TiSCH architecture allows RPL parents to adjust
 dynamically, and independently from the PCE, the amount of bandwidth that
 is used to communicate between themselves and their children, in both
 directions"  ? So this means a PCE-schedule be overidden or modified as it
 is disseminated across the network ?

 [PT] The PCE would have precedence and the nodes could use the rest of the
 CDU matrix. What about adding

             Note that a PCE is expected to have precedence in the
 allocation,
             so that a RPL parent would only be able to obtain portions
 that are
             not in-use by the PCE.

 Section 6.5  "The chunks is the basic unit  of ownership..."  should
 probably start with "The chunk..."

 [PT] fixed

 Section 6.5 "The 6TiSCH architecture introduces the concept of chunks to
 operate such spectrum distribution for a whole group of cells at a time"
 is a chunk a set of "contiguous" cells in the SlotFrame ?

 [PT] No, it is an arbitrary bunch of cells, but if nodes have a single
 radio, then it makes little sense to have more than one cell at a given
 slotoffset....

-- 
--------------------------------+--------------------------------
 Reporter:  [email-masked]  |      Owner:  [email-masked]
     Type:  enhancement         |     Status:  new
 Priority:  major               |  Milestone:  milestone1
Component:  architecture        |    Version:  1.0
 Severity:  Active WG Document  |   Keywords:
--------------------------------+--------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/6tisch/trac/ticket/28>
6tisch <http://tools.ietf.org/6tisch/>

---

From: "6tisch issue tracker" <[email-masked]>
Date: Tue, 28 Oct 2014 15:07:09 -0000

Changes (by [email-masked]):

 * status:  new => closed
 * resolution:   => fixed

-- 
--------------------------------+---------------------------------
 Reporter:  [email-masked]  |       Owner:  [email-masked]
     Type:  enhancement         |      Status:  closed
 Priority:  major               |   Milestone:  milestone1
Component:  architecture        |     Version:  1.0
 Severity:  Active WG Document  |  Resolution:  fixed
 Keywords:                      |
--------------------------------+---------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/6tisch/trac/ticket/28#comment:1>
6tisch <http://tools.ietf.org/6tisch/>