Patent ID: 8295164

Claim:
A network-connection redundant method for devices with cascade networking capability, comprising: initializing a network with a plurality of network nodes and one or more networking devices, wherein each network node has at least two network ports and one or more device ports, and each network node connects to the one or more networking devices via the device ports, and the each networking device at least has two network ports connecting the same one or different network nodes, and the networking device connects an external network via the network node; wherein the plurality of network nodes are disposed in two or more local area networks with various network types, and the network nodes are connected across two end ports of the one or more interconnected networking devices; defining roles of ports for each device port of each network node according to network packets generated by each network node and each networking device, wherein the roles of ports are a plurality of forward ports and one or more blocked ports; each network node periodically broadcasting to the types of local area networks or confirming receiving a connection-confirmation packet from the local area networks; determining whether any connection changes according to a relative response packet; if the connection does not change, continuously broadcasting connection-confirmation packet; if the connection changes, including failure of connection, failure of device, and modification of connection, redefining the roles of ports for each device port; and accomplishing a redundant connection.