Sender                    Receiver
          |-----W=0,FCN=6,Seq=1----->|
          |-----W=0,FCN=5,Seq=2--X   |
          |-----W=0,FCN=4,Seq=3----->|
          |-----W=0,FCN=3,Seq=4--X   |
          |-----W=0,FCN=2,Seq=5----->|
          |-----W=0,FCN=1,Seq=6----->|                     __
DL Enable |-----W=0,FCN=0,Seq=7----->| Waits for          |W=0
       (no ACK)                       next DL opportunity |FCN=5,Seq=2
          |-----W=1,FCN=6,Seq=8--X   |                    |FCN=3,Seq=4
DL Enable |-----W=1,FCN=7,Seq=9----->| Missing Fragment<-- W=1
          |<-Compound ACK,W=0,1, C=0-| Bitmap W=0:1010110 |FCN=6,Seq=8
          |-----W=0,FCN=5,Seq=11---->|        W=1:0000001  --
          |-----W=0,FCN=3,Seq=12---->|
          |-----W=1,FCN=6,Seq=13---->| All fragments received
DL Enable |-----W=1,FCN=7,Seq=14---->|
          |<-Compound ACK, W=1, C=1 -| C=1
        (End)