Method of and apparatus for processing virtual local area network tag frame

A method of processing a virtual local area network (VLAN) tag frame using an apparatus placed between a gigabit passive optical network (GPON) master and an Ethernet switch, the apparatus for processing the VLAN tag frame by using filtering data base (FDB) memory for storing VLAN tag frame information, the method comprising:

• performing an FDB write operation by determining whether learning has been performed by comparing a source address (SA) in a received Ethernet data frame from the Ethernet switch to a value stored in the FDB memory and inputting the SA in the Ethernet data frame and a VLAN identification (VID) in the FDB memory;
• and
• creating a VLAN tag by looking up a destination address (DA) of a data frame toward the GPON master and the SA in the FDB memory, and performing an FDB read operation by inserting the VLAN tag to the data frame, wherein the VLAN tag is inserted in the data frame by the apparatus placed between the GPON master and the Ethernet switch,
• wherein performing the FDB write operation comprises:
• storing the SA and the VID for each port;
• checking whether a memory write address for the FDB memory has a value 0;
• comparing the memory write address with a memory read address for the FDB memory if the checked memory write address does not have the value 0;
• initializing the memory write address and re-storing the SA and the VID if the memory write address is identical to the memory read address according to the comparison result and
• performing the FDB write operation if the memory write address has the value 0, or if the memory write address does not have the value 0 and is not identical to the memory read address.