Patent Document ID: 8484322
Application ID: 12028159
Patent Flag: 1

Claim One:
1. A method for reconfiguring an initial network into first and second partial networks including respective first and second routers each communicably coupled to an external network, the method comprising: configuring the initial network as a subnet by assigning initial IP addresses to devices within the initial network using an initial IP address block defining an initial address range of the initial IP addresses, the initial IP address block including an initial host address portion identifying relative positions of the initial IP addresses within the initial network; detecting an interruption of data communication between the first and second routers; determining that the initial network has been separated into first and second partial networks based on the detection of the interruption of data communication between the first and second routers; defining first and second IP address blocks for assigning first and second IP addresses to devices within the respective first and second partial networks, the first IP address block defining a first address range of the first IP addresses and including a first host address portion identifying relative positions of the first IP addresses within the first partial network, the second IP address block defining a second address range of the second IP addresses and including a second host address portion for defining relative positions of the second IP addresses within the second partial network, wherein each of the first and second IP address blocks is defined so that the respective first and second address ranges are mutually disjoint and both are included in the initial address range, by defining the first and second host address portions each having a common bit length that is not greater than a bit length of the initial host address portion and is minimum among bit lengths each enabling the first and second host address portions to identify the first and second IP addresses, respectively; configuring the first and second partial networks as subnets by assigning IP addresses that are generated based on the defined first and second IP address blocks, to devices within the first and second partial networks, respectively; and transferring packets between the devices in the first and second partial networks and the external network via one of the first and second routers, wherein the common bit length of the first and second host address portions is obtained by performing a procedure including: counting a first set of in-use IP addresses that are currently used for the first partial network, to determine counted number of the first set of in-use IP addresses to be a first IP address count value for the first partial network; counting a second set of in-use IP addresses that are currently used for the second partial network, to determine counted number of the second set of in-use IP addresses to be a second IP address count value for the second partial network; determining a value maximum between the determined first and second IP address count values to be a maximum IP address count value; and determining a minimum bit length of a bit sequence that enables the bit sequence to represent the determined maximum IP address count value, to be the common bit length.