Abstract: A mobile communication terminal and a management method for an always preserved PDP context using for the mobile communication terminal, in which not delivering data to the mobile communication terminal from a push contents server can be avoided and also reestablishing an undesirable always preserved PDP context can be avoided, are provided. The timer in the mobile communication terminal is started at the time when the mobile communication terminal moved from a service area to an out of service area. The full measuring time value in the mobile communication terminal is set to be smaller than that of a PRAUT (periodic routing area update timer) in an RNC (resource network controller).

Abstract: A mobile/portable terminal being connected at any time to a PDP (Packet Data Protocol) context in order to receive a push service from a server is provided with PDP Context Management which performs a health check between the mobile/portable terminal and a terminal point of the PDP context on the side of a network.

Abstract: In a ring network, a network element having no routing protocol is connected between first and second nodes, and the first node has a link status table indicating link states of the network element and the second node. The first node transmits a health check polling message at periodic intervals to the network element as well as to the second node to elicit responses therefrom, updates each of the link states when no response is returned, examines the link status table at periodic intervals, and broadcasts a message to the network for updating a routing table of a third node of the network so that an alternate route is established from the third node to the network element via the first node if the link status table indicates that there is a faulty condition between the network element and the second node. The third node transmits a network management message to the network element via the alternate route according to the updated routing table.

Abstract: In a network including a simple element having no routing function, each node includes a health-check function to keep track of the respective statuses of its managing simple elements. A source node broadcasts an address request signal (TARP) including the ID of a destination simple element and then waits for its response signal. Each node, receiving the address request signal, further broadcasts it when neither managing nor normally communicating with the destination simple element, and otherwise sends the response signal back to the source node. When the response signal is received from another node, the source node transmits a management message to the destination simple element via the node sending the response signal. Since it is checked that each node normally communicates with its managing simple elements by the health-check function, the node cannot send the response signal in the case where some failure exists between the node itself and the destination simple element.

Abstract: A network system comprises a terminal storing a update data file, a gateway device having a temporary memory, and a network comprising a plurality of nodes. Each node is provided with an active memory for storing a current data file and at least a backup memory for storing the update data file. Data of the update data file are sequentially transferred from the terminal to the backup memory of each node through the gateway device in which the date are stored into the temporary memory. After the update data file has been stored in the backup memory, the update data file is caused to be active and the current data file to be non-active.

Abstract: An interlocking apparatus capable of expanding a network while effectively using survivability of a self-healing ring, including a ring network connecting a plurality of nodes having a loop back function and a supplementary node connected to the first and second nodes of the ring netwrok. In the first node, a service selector selects a normal signal from the two signals sent from the second node and the supplementary node to output the selected signal to a next stage node. In the supplementary node, a path selector selects a normal signal from the two signals sent from the first and second nodes to output the selected signal outside the ring network. The service selector and the path selector include a monitor controller for always selecting the normal signal from the two input signals and further judge and determine a trigger for executing a switching or a switching direction in an autonomous distributed manner.

Abstract: A composite communication network of a hierarchical structure including a subnetwork at least in part thereof has a gateway (GW) node having a control message communication medium which includes three or more routes. Routing of the network layer level is performed between GW nodes and routing of the data link layer level is conducted in the ring subnetwork. Each node in the ring has an NE address to be distinguished in the ring and a routing table which shows a routing direction corresponding to a destination node. When the GW node in the ring including a target of a control message receives a message, the GW node sets an NE address of the target node in the packet of the message as a destination address, and processes the packet for transmitting to the control message communication medium indicated in the routing table.