Patent ID: 7496055
Filing Date: 2009-02-24
Classification: H04L

Abstract:
1. A layer 2 loop detection apparatus using a Simple Network Management Protocol (SNMP) manager that monitoring target is a layer 2 network having a plurality of layer 2 switches, comprising: a unit recognizing a topology of the layer 2 network at normal time by collecting Management Information Base (MIB) information including information concerning ports of the plurality of layer 2 switches from the plurality of layer 2 switches through SNMP communication; a unit discriminating, based on the topology recognition processing, a blocking port for traffic blocking set under a Spanning Tree Protocol (STP); a unit setting the discriminated blocking port as a monitoring point and periodically monitoring a state thereof; and a unit performing detection of a layer 2 loop by re-collecting a part of the MIB information from the plurality of layer 2 switches through SNMP communication and re-recognizing the topology of the layer 2 network, the detection of the layer 2 loop being triggered by a change of the state of the blocking port; wherein at a time when a part of the MIB information is re-collected through the SNMP communication, if the MIB information cannot be collected from one of the plurality of layer 2 switches, a location of the layer 2 loop is detected by detecting that every port connected to the layer 2 switch is set as a designated port.