|
Hi Gabriel,
There is some comments about the last draft,
thanks.
In Section 11, the draft mentions that a special
format of "Mesh Delivery" field should be used when Broadcast or Multicast. This
kind of field is called as Mesh Broadcast or Multicast Delivery Field
and a "Sequence Number" is added.
For Source Node, it will be clear that which kind
of format it should use. But for Destination Node or Relay Node, looks like
there will be some confusion when they trying to explain this
format.
The cause of such confusion is the way inbound
Node identifying such kind of field format. As the draft mentioned, the
destination address is the identification of such kind of
field. However, for the Final Destination Address
is behind the Sequence Number, the inbound Node will be unaware of the
existence of this field before it check the Final Destination Address. If
inbound Node handle all Broadcast Delivery Field as the normal "Mesh
Delivery" field, when it begins to check the Final Destination Address,
there will be 8-bits shift of the right position. This scenario must lead
to an mistake.
There is also another way to identify the Broadcast
Delivery Field. That is checking the destination MAC address in the IEEE
802.15.4 header (0xFFFF). But in practice, an IEEE 802.15.4 broadcast
frame can't be delivered to every END DEVICE (RFD). This is because the END
DEVICE disable its transceiver during CAP when there is no frame
directly sent to it.
To avoid such incorrect scenario, one flag may be
needed in the fixed filed (in Adaptation Header). That make all node could
recognize the special Broadcast Delivery Field in right way.
Regards,
|
_______________________________________________ 6lowpan mailing list [email protected] https://www1.ietf.org/mailman/listinfo/6lowpan
