L2 switch detection method and program

1 . A method for detecting unregistered L2 (Layer-2) switches in a network, comprising:

a first step of 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 (media access control) addresses of L2 switches Sj have been registered;

a second step of detecting MAC addresses M(Zi) (1≤i) 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 step,

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 step of 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 step;

a fourth step of registering said MAC addresses M(Xk) identified in the third step in the management table.

2 . The method according to claim 1 , wherein the second step comprises:

(1) Extracting the MAC address common to both P(Sx,m) and P(Sy, n) as the MAC addresses of one or more apparatuses existing between L2 switches Sx and Sy,

wherein said P(Sx,m) is switch-port information P(Sx,m) of L2 switch Sx, in which MAC addresses M (Sy) is detected at port-number m, and said P(Sy,n) is switch-port information P (Sy,n) of L2 switch Sy, in which MAC addresses M (Sx) is detected at port-number n; and

(2) Identifying the MAC addresses M(Zi) that are not registered in the management table from among the MAC addresses extracted in above (1).

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

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 (media access control) addresses M(Zi) (1≤i) 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.

4 . The computer program according to claim 3 , wherein the second executable process comprises:

(1) Extracting the MAC address common to both P(Sx,m) and P(Sy, n) as the MAC addresses of one or more apparatuses existing between L2 switches Sx and Sy,

wherein said P(Sx,m) is switch-port information P(Sx,m) of L2 switch Sx, in which MAC addresses M (Sy) is detected at port-number m, and said P(Sy,n) is switch-port information P(Sy, n) of L2 switch Sy, in which MAC addresses M (Sx) is detected at port-number n; and

(2) Identifying the MAC addresses M(Zi) that are not registered in the management table from among the MAC addresses extracted in above (1).