[lp-wan] retransmission in the last window

[Arun <[e-mail]>]

Hi Carles and all, 

Scenario : More than one fragment is lost in the last window of ACK always mode; 
Per my understanding, this is bit different than the retransmission behavior that is observed in non-last window.
Since there can be lesser number of fragments than the window size in the last window the receiver has to validate MIC and send ACK for every received packet.
In other cases(other than the last window), the receiver shall wait until the least CFN of the lost fragments before sending the ACK with bitmap.

example of the expected sequence: (took most part of it from Fig:20 draft-05)

   	 Sender               Receiver
             |-----W=1, CFN=6----->|
             |-----W=1, CFN=5----->|
             |-----W=1, CFN=4--X-->|
             |-----W=1, CFN=3----->|
             |-----W=1, CFN=2--X-->|
             |-----W=1, CFN=1----->|
             |-----W=1, CFN=0----->|
             |<-----ACK, W=1-------|bitmap:11010111
             |-----W=1, CFN=4----->|
             |-----W=1, CFN=2----->|
             |<-----ACK, W=1-------|no bitmap
             |-----W=0, CFN=6----->|
             |-----W=0, CFN=5----->|
             |-----W=0, CFN=4--X-->|
             |-----W=0, CFN=3--X-->|
             |-----W=0, CFN=2--X-->|
             |-----W=0, CFN=7----->|MIC checked
             |<-----ACK, W=0-------|bitmap:11000001
             |-----W=0, CFN=4----->|MIC checked 
             |<-----ACK, W=0-------|bitmap:11100001
	     |-----W=0, CFN=3----->|MIC checked 
             |<-----ACK, W=0-------|bitmap:11100001
	     |-----W=0, CFN=2----->|MIC checked 
	     |<-----ACK, W=0-------|no bitmap
			           (End)

is this the expected behavior? 
if yes, an example in the "Appendix" of the draft and a discussion in "Baseline mechanism" section would be useful (please ignore if it is already planned in 06 version).

Thanks,

-- 
Arunprabhu Kandasamy
arun at ackl.io

2 bis rue de la Châtaigneraie
35510 Cesson-Sévigné 
France 
Phone: [phone]