(A)(B)
   |  |
   |  | All-1 & rcv_W==cur_W & RCS!=OK        All-0 empty(Wn)
   |  | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~     +-+  ~~~~~~~~~~
   |  | sendACK([cur_W,Bmp_n],C=0)       | v  sendACK([Wn,Bmp_n])
   |  |                      +===========+=++
   |  +--------------------->+   Wait End   +-+
   |                         +=====+=+====+=+ | All-1
   |     rcv_W==cur_W & RCS==OK    | |    ^   | & rcv_W==cur_W
   |     ~~~~~~~~~~~~~~~~~~~~~~    | |    +---+ & RCS!=OK
   |  sendACK([cur_W,Bmp_n],C=1)   | |          ~~~~~~~~~~~~~~~~~~~
   |                               | | sendACK([cur_W,Bmp_n],C=0);
   |                               | |          Attempts++
   |All-1 & Full([cur_W,Bmp_n])    | |
   |& RCS==OK & sync==0            | +-->* ABORT
   |~~~~~~~~~~~~~~~~~~~            v
   |sendACK([cur_W,Bmp_n],C=1)   +=+=========+
   +---------------------------->+    END    |
                                 +===========+