Data package transmitting method and network exchanger adopting said method

This invention relates to transmitting method of data packet and a network exchanger containing multi connecting ports, a label exchange ruling table, a multi-casting cross-reference list, a virtual local area network cross-reference list and a label setting device, composed of receiving a data packet according to the multi-cast information, label exchange ruling table and virtual local area network cross-reference list, a multi-cast port mask, a label exchange rule and a label additional rule correspondingly. Said data packet is transmitted via the connects port in opposite of said multi-cast port mask, and optionally adding the relating virtual local area network label to the data packet in accordance with the label addition rule and label exchange rule.