Patent ID: 7760762

Claim:
A method for controlling a physical bandwidth of a ring-based network by employing a ring application of a data link layer that operates in a physical layer, the method comprising: a) generating a first control frame; b) requesting each of a plurality of node apparatuses included in the ring-based network to confirm whether the bandwidth can be changed by transmitting the first control frame to all of the plural node apparatuses included in the ring-based network; c) generating a second control frame; d) instructing each of the plural node apparatuses to prepare for the bandwidth change by transmitting the second control frame to all of the plural node apparatuses upon receiving a confirmation that the bandwidth can be changed from all of the plural node apparatuses; e) generating a third control frame; f) reporting that the preparation for the bandwidth change is completed by transmitting the third control frame to all of the plural node apparatuses; and g) changing the bandwidth by using a bandwidth changing function of the ring application upon receiving the third control frame reporting the completion of the preparation for the bandwidth change.