[Roll] DTSN increment

[Rahul Jadhav <[e-mail]>]

Hi All,

I have specific query regarding handling of DTSN increments. DTSN
increments are handled differently in case of storing mode vs non-storing
mode.

6550 states,
"
   In a Non-Storing mode of operation, a DTSN increment will also cause
   the immediate children of a node to increment their DTSN in turn,
   triggering a set of DAO updates from the entire sub-DODAG.
   Typically, in a Non-Storing mode of operation, only the root would
   independently increment the DTSN when a DAO refresh is needed but a
   global repair (such as by incrementing DODAGVersionNumber) is not
   desired.  Typically, in a Non-Storing mode of operation, all non-root
   nodes would increment their DTSN only when their parent(s) are
   observed to do so.
"

Based on this wordings, in non-storing mode, the DTSN update is controlled
by the root only (having said that, the RFC does not mandate it).

What i don't understand is, why DTSN increment is handled differently for
storing and non-storing mode?
Also when the DTSN is incremented by the child node, isn't it desired that
DIO trickle timer is reseted, since otherwise the DIO (with incremented
DTSN) may be sent out (very) late and thus DAO update may take huge time
(depending upon where the trickle timer rests currently).

Regards,
Rahul