def l1_bit_rate(l2br, pps, ifg, preamble):
    """
    Return the l1 bit rate
    :param l2br: l2 bit rate int bits per second
    :param pps: packets per second
    :param ifg: the inter frame gap
    :param preamble: preamble size of the packet header in bytes
    :return: l1 bit rate as float
    """
    return l2br + (pps * ifg * preamble)