[lp-wan] re-order header field request

[Arun <[e-mail]>]

Hi all,
Absence of window bit in the last fragment of the packet makes it tricky
to unmarshall the header at the receiver.
As I see it, the receiver up front shall know the length of the CFN
field depending on the Window size configured but doesn't know to
anticipate the last fragment unless indicated by CFN.
So I think,  we need to maintain same order on all fragment headers.

existing;

      		<------------ R ---------->
                          <--T--> 1 <--N-->
               +-- ... --+- ... -+-+- ... -+
               | Rule ID | DTag  |W|  CFN  |
               +-- ... --+- ... -+-+- ... -+

shall be;
     		<------------ R ---------->
                          <--T--> <--N--> 1
               +-- ... --+- ... -+- ... -+-+
               | Rule ID | DTag  |  CFN  |W|
               +-- ... --+- ... -+- ... -+-+

and for the last fragment
   		<------------ R ---------->
                          <--T--> <--N--> 
               +-- ... --+- ... -+- ... -+-+
               | Rule ID | DTag  |  CFN  |MIC
               +-- ... --+- ... -+- ... -+-+


what do you think?


thanks,
Arun