This object gives the initial send window size advertised by the remote peer for this VPDN session, which is meaningless when the session's sequencing state is 'none' because no sequencing was negotiated. It helps an administrator see how much unacknowledged traffic the far end permitted itself to send when the session's flow control was set up. For example, comparing this initial value with the session's current window size shows whether the effective window has shrunk since the tunnel was established.