Patent ID: 7707306

Claim:
A method of starting a first routing device connecting a plurality of networks to which a plurality of routing devices are connected, wherein each routing device stores master router data for each network to which the routing device is connected and network identification data, wherein the master router data stored by each routing device indicates whether the respective routing device is a master router or a slave router with respect to each network to which the respective routing device is connected, wherein, with respect to each network, one of the routing devices connected thereto that is also connected to a network nearer to a parent router, which assigns the network identification data to identify the networks, is the master router, wherein, with respect to each network, one or more of the routing devices connected thereto that is not connected to the network nearer to the parent router, is the slave router, and wherein the network identification data of each respective routing device identifies a network to which the respective routing device is connected, the method of starting the first routing device comprising: requesting, by the first routing device, the master router data from each routing device connected to the networks to which the first routing device is connected; acquiring the master router data in response to the requesting of the master router data; determining, from the acquired master router data, a number of detected master routers connected to the networks to which the first routing device is connected; and disabling a router function of the first routing device when, in relation to the networks to which the first routing device is connected, the determined number of detected master routers is zero or two or more, such that a loop path is prevented from forming between the first routing device and the plurality of routing devices, wherein the routing function of the first routing device allows the first routing device to connect to a network, such that when the router function is disabled, the first routing device cannot connect to the network.