[Roll] No path DAO treated as new

[Rahul Jadhav <[e-mail]>]

Hello All,

Section 9.2.2. of RFC6550 says that a No-Path DAO message should always be
processed as a "new" message (i.e. igoring the PathSequence value related
to the target) ...
I have problem with a scenario where if a node sends NPDAO (to old path)
and DAO to the new path for the same target ... and if for some reason
NPDAO reaches after the DAO to the common parent then it will clear the
routes because NPDAO is alway processed as "new" message.
Consider an eg network,
    A
    |
    B
   / \
  /   \
 C     D
  :   /
   : /
    E
Node E switches from C to D, E sends an NPDAO to C, and regular DAO to D.
If B receives NPDAO after DAO, then won't it result in incorrect
invalidation of routes. My point is, the NPDAO processing should also have
honored the PathSequence value before processing. But the spec text clearly
and specifically talks about treating NPDAOs as "new".
Any thoughts on why special treatment for NPDAO was considered?

Thanks,
Rahul