Abstract: An access node run as a packet switching apparatus enables IP connection services for a plurality of access methods; e.g., relatively low-speed IP connection, high-speed IP connection, and mobile network IP connection. By using this apparatus of the present invention, cost can be reduced and upgrading to advanced access networks and access services is easily carried out. Provision of the above access nodes implements upgrade-type network services common for diverse protocols. Each access node retains a pathfinding table to which input port, input tunnel identifier and input session identifier entries in a set are registered per session. When routing a packet, by looking up the set of these entries matching with the packet, the associated output port, output tunnel identifier, and output session identifier are obtained. After processing for the packet, appropriate for one of the plurality of access methods and network services, the node forwards the packet over the routed path.

Abstract: A packet switching apparatus is constructed by a basic module disposed in the apparatus casing and an additional module disposed on the outside of the apparatus casing. The basic module has a common processing function irrespective of an access method and a service type, an interface accommodating lines to be connected to the Internet, and a plurality of interface boards conformed to a specific access method by which a hardware scale may be small. Only the basic module functions as a packet switching apparatus, and a processing function peculiar to each access method and service type is executed by the additional module.

Abstract: A packet handler includes an interface circuit of an ATM handler corresponding in one-to-one relation to each input/output port of an ATM switch. A switch interface including a disconnection circuit and a distribution circuit controls the cell flow from each interface circuit to a corresponding input port and the cell from the output ports of the ATM switch to each interface circuit. In a pet of interface circuits, one redundant transmission path can be replaced arbitrarily with two nonredundant independent transmission paths. The ATM communication system can thus accommodate redundant transmission paths and nonredundant transmission paths in an arbitrary ratio.