Network system, switch, and server

A server for use in a network system, which controls a plurality of switches that interconnect a plurality of terminals by receiving and forwarding packets originating from the terminals, the server comprising:

• storage means for storing a list of identifiers of the terminals, in association with logical groups to which the terminals belong;
• searching means for searching said storage means in response to a query from one of the switches;
• transmission means for receiving a search result from said searching means and sending the search result to the switch that has sent the query;
• supposition means for suggesting a specific logical group to which a source terminal in question is supposed to belong, based on the identifier of the source terminal, when said searching means has failed to provide the requested information;
• another storage means for storing a list of the switches being available in the network system, in association with a list of the logical groups that can be assigned to the terminals belonging to each switch's local terminal group,
• wherein, when the query is received from a requesting switch, said server consults said another storage means to find logical groups relevant to said requesting switch, and if the relevant logical groups do not include the logical group to which said source terminal in question is supposed to belong, prevents enrollment of said source terminal in a non-included logical group.

A computer-readable medium which stores a computer program being designed to run on a computer in order to cause the computer to fiction as a server comprising:

• storage means for storing a list of identifiers of terminals, in association with logical groups to which the terminals belong;
• searching means for searching said storage means in response to a query from one of the switches;
• transmission means for receiving a search result from said searching means and sending the search result to the switch that has sent the query;
• supposition means for suggesting a specific logical group to which a source terminal in question is supposed to belong based on the identifier of the source terminal, when said searching means has failed to provide requested information;
• and
• another storage means for storing a list of the switches being available in the network system, in association with a list of the logical groups that can be assigned to the terminals belongings to each switch's local terminal group;
• wherein, when the query is received from a requesting switch, the server consults said other storage means to find logical groups relevant to the requesting switch, and if the relevant logical groups do not include the logical group to which said source terminal in question is supposed to belong, prevents enrollment of said source terminal in a non-included logical group.