Patent ID: 9497077
Filing Date: 2016-11-15
CPC Classification: H04L

Claim Text:
1. An apparatus for performing loop-free transmission in a communication network, the apparatus comprising: a plurality of ports; a controller including a first processor configured to generate monitoring frames that are transmitted to another apparatus, so as to monitor a connection state of the communication network; a memory configured to include port-state information that stores a port state in association with each of the plurality of ports; and an interface card including a second processor configured: the memory is further configured to include filter information that stores information indicating whether or not the STP is valid for a received frame, in association with a combination of control information and port-identification information identifying each of the plurality of ports, the control information identifying information stored in a predetermined region of the received frame; the second processor of the interface card determines whether or not a spanning tree protocol (STP) is applied to the first frame, by searching the filter information for the combination of the control information coinciding with information stored in the predetermined region of the received first frame and the port-identification information identifying the first port; and when it is determined that the STP is applied to the first frame, the second processor of the interface card discards the first frame received via the first port for which the stopped state is set in the port-state information.