void TcpSocketBase::RefreshWindowSize(TcpHeader &header)

{

    NS_LOG_FUNCTION (this << header);

//    if connection is not established, window size is set  from packets

//    because reordering cannot occur in stage of 3-way handshakes , because only 1 packet in one time in way.

    if (m_state  < ESTABLISHED)

    {

        m_rWnd = header.GetWindowSize ();

        m_rWnd <<= m_rcvScaleFactor;

        NS_LOG_DEBUG ("updating rWnd to " << m_rWnd);

        return;

    }

//   if connection established and not ends.

//   And new sequence and ack number were received less than which was before.

//   -  it's mean that reordering occurs.

    bool reorder = false;

    if (header.GetAckNumber () < m_highestAckNumber)

    {

        reorder = true;

    }

    if (header.GetSequenceNumber () < m_highestSequenceNumber)

    {

        reorder = true;

    }

    if (reorder == false)

    {

        m_rWnd = header.GetWindowSize ();

        m_rWnd <<= m_rcvScaleFactor;

        m_highestAckNumber = header.GetAckNumber();

        m_highestSequenceNumber = header.GetSequenceNumber ();

        NS_LOG_DEBUG ("updating rWnd to " << m_rWnd);

    }

    else

    {

        NS_LOG_DEBUG ("Detected reordering; not updating rWnd");

    }

}