Data packet transmission method and network switch applying same thereto

A data packet transmission method for use in a network switch having a plurality of connection ports, comprising steps of:

• receiving a data packet;
• acquiring a multicast port mask in response to a multicasting information of said data packet;
• and
• transmitting said data packet to destination ports according to said multicast port mask, and selectively affixing a VLAN tag to said data packet according to a first tagging rule.

A network switch, comprising:

• a plurality of connection ports for tranceiving a data packet therefrom;
• a tag substitution rule table defining a tag substitution rule;
• a VLAN reference table defining the correlation of a tagging rule with a VLAN information of said data packet;
• a multicast reference table defining a relationship of a multicast port mask with a multicasting information of said data packet;
• and
• a tag determination device optionally affixing a VLAN tag to said data packet according to said tag substitution rule and said tagging rule by looking up said VLAN reference table and said multicast reference table when said data packet is tranceived through destination ports according to said multicast port mask.