Abstract: A virtual local area network (VLAN) system that uses an energy saving path includes a terminal which data is input to and output from by a user, a first switch configured to connect the terminal to a network, and a plurality of second switches connected to the first switch to form a trunk link. When traffic load on at least one of the plurality of second switches is less than a lower threshold in a situation in which packets are transmitted using an such that the packets are concentrated on a specific path of the trunk link.

Abstract: Provided are a method of controlling packet transmission in a network system and a network system that transmits a packet using a pseudo-transmission control protocol (TCP) agent. The method includes, when a packet is received from a transmitting device or a previous router, storing, at a router, the packet in a buffer and determining whether traffic exceeds a packet processing capacity, when it is determined that the traffic exceeds the packet processing capacity, controlling, at the router, an incoming packet rate to be reduced, when a congestion window is not filled with the packet to be transmitted to a next router or a receiving device due to the reduction in the incoming packet rate, waiting, at the router, until the congestion window is fully filled with a packet received thereafter, and transmitting, at the router, the packets filling the congestion window to the next router or the receiving device.

Abstract: A virtual local area network (VLAN) system that uses an energy saving path includes a terminal which data is input to and output from by a user, a first switch configured to connect the terminal to a network, and a plurality of second switches connected to the first switch to form a trunk link. When traffic load on at least one of the plurality of second switches is less than a lower threshold in a situation in which packets are transmitted using an such that the packets are concentrated on a specific path of the trunk link.