Patent ID: 8356093

Claim:
A management apparatus for managing logical topology information among a plurality of communication apparatuses, wherein said management apparatus comprises one or more computers and: a first storage unit for managing ports of said communication apparatus assigned to each VLAN; a second storage unit for storing a physical connection relation between said ports of said communication apparatuses; a third storage unit for storing links indicating logical connections between said ports constituting link aggregation of said communication apparatus; a fourth storage unit for storing belongings of said VLAN to a link like a ring shape among said communication apparatuses; a logical topology estimating unit configured for generating a logical topology in accordance with said second and third storage units; and a monitoring unit configured for receiving state information from said communication apparatuses, wherein: a portion of information in said first to fourth storage units is updated in accordance with said state information acquired by said monitoring unit; and said logical topology estimating unit is configured for generating a logical topology by referring to said updated first to fourth storage units, wherein said management apparatus is configured: to select one VLAN by referring to said first storage unit; to select a link in a transferable state from links constituting ports assigned to said selected one VLAN, by referring to said second storage unit; to judge whether said selected link in a transferable state of a port constitutes link aggregation by referring to said third storage unit, and if said selected link constitutes link aggregation, one of the links constituting link aggregation is used as a link of said logical topology; to judge whether said selected one VLAN belongs to said ring, by referring to said fourth storage unit; to release a link in front of a blocking port if all links of the ring to which said selected one VLAN belongs are normal; and to generate a logical topology corresponding to links assigned to said selected one VLAN by using links other than the link in front of said blocking port, wherein said state information is one of: a first notice for notifying that an abnormal state occurs in a ring; a second notice for notifying that an abnormal state occurs in a link or said communication apparatus; a third notice for notifying that a ring recovers a normal state; and a fourth notice for notifying that a link or said communication apparatus recovers a normal state.