Patent ID: 7146438

Claim:
A method for controlling packet flow, comprising: determining priority data of a packet received by one of a plurality of ports, wherein the priority data are determined by: determining whether the priority data are designated to the one of the plurality of ports at which the packet is received or whether the priority data are designated to the packet and by outputting a first signal when the priority data is designated to the one of the plurality of ports at which the packet is received and a second signal when the priority data is not designated to the one of the plurality of ports at which the packet is received; determining whether the packet is a VLAN packet or an IP packet when the priority data is designated to the packet; and determining a priority by reading a priority field data of the VLAN packet or the IP packet and by outputting a third signal when the priority of the VLAN packet or the IP packet is over a predetermined critical value and outputting a fourth signal when the priority of the VLAN packet or the IP packet is under the predetermined critical value in the case where the priority data is designated to the VLAN packet or the IP packet; measuring bandwidth data of each port; outputting state data of each port of the plurality of ports by using the priority data and the bandwidth data; determining whether an address pointer of a packet memory exceeds a predetermined limit value by monitoring the packet memory; selecting at least one port of the plurality of ports to control packet flowby using the state data when the address pointer of the packet memory exceeds the predetermined limit value; and directing the selected at least one port to control the packet flow.