Link trace frame transfer program recording medium, switching hub, and link trace frame transfer method

A switching hub, comprising:

• a MAC learning table storing a correspondence relationship of a MAC address and port identification information, the port identification information identifying a port for transferring a frame to which the MAC address is assigned;
• an updating unit updating the MAC learning table;
• a readout unit reading out a MAC address of a link trace frame;
• a first transfer unit transferring the link trace frame via a port determined by a correspondence relationship in the MAC learning table;
• a storage unit storing a correspondence relationship of a predetermined MAC address and port identification information;
• a saving unit saving a correspondence relationship set as an object to be deleted in the storage unit at a time of updating the MAC learning table;
• a second transfer unit transferring the link trace frame via a port determined by a correspondence relationship saved in the storage unit upon determining that there is no correspondence relationship relevant to the MAC address assigned to the received link trace frame in the MAC learning table;
• and
• a responding unit sending a response frame to a switching hub which is an originator of the link trace frame simultaneously with transfer of the link trace frame by the first transfer unit and second transfer unit.

A link trace frame transfer method, comprising:

• updating a MAC learning table storing a correspondence relationship of a MAC address and port identification information identifying a port for transferring a frame to which the MAC address is assigned,
• executing a first transfer including reading a MAC address of a link trace frame and transferring the link trace frame via a port determined by a correspondence relationship in the MAC learning table;
• saving a correspondence relationship set as an object to be deleted in a predetermined storage unit at a time of updating the MAC learning table;
• executing a second transfer including transferring the link trace frame via a port determined by a correspondence relationship saved in the storage unit upon determining that there is no correspondence relationship relevant to the MAC address assigned to the received link trace frame in the MAC learning table;
• and
• sending a response frame to the switching hub which is an originator of the link trace frame simultaneously with transfer of the link trace frame at execution of the first transfer and second transfer.

A link trace frame transfer method, comprising

• transferring a link trace frame to intermediate switching hubs between an origin and a destination;
• sending a response frame from each of the switching hubs to the origin of the link trace frame when transferring the link trace frame towards the destination;
• and
• determining a location of a fault by identifying switching hubs returning the response.