This object reports the send window size currently in effect for this VPDN session and, like the related window-size objects, is not meaningful when the session's sequencing state is 'none'. It lets an administrator see, moment to moment, how much sequenced traffic this end is currently permitted to have unacknowledged on the wire, which can shrink from its initial value under congestion. For example, a current window size well below the session's initial remote window value could point to the far end throttling back due to loss on the tunnel path.