L2 switch detection method and program

A computer program embodied on a non-volatile computer readable medium of network monitoring apparatus H to execute processes for detecting unregistered L2 (Layer-2) switches in a network, comprising of:

• a first executable process for collecting switch-port information from L2 switches Sj (1≤j) registered in the management table by monitoring apparatus H,
• wherein, in the management table, the MAC addresses of L2 switches Sj have been registered;
• a second executable process for detecting MAC addresses M(Zi) (1≤j) of one or more unregistered apparatuses existing between L2 switches Sx and Sy registered in the management table based on said switch-port information collected from L2 switches Sx and Sy in the first executable process,
• wherein said MAC addresses M(Zi) are detected by identifying the MAC addresses that are contained in the collected switch-port information of both L2 switches Sx and Sy;
• a third executable process for identifying MAC addresses M(Xk) (1≤k) of one or more L2 switches Xk from among said MAC addresses M(Zi) detected in the second executable process;
• a fourth executable process for registering said MAC addresses M(Xk) identified in the third executable process in the management table.